Next  fresh install F20 &  Havana via native repo.

Issue seems to be related to https://bugzilla.redhat.com/show_bug.cgi?id=1051593

Straight forward `packstack --alinone`  install via native Havana repo with no problems.
Openstack-status is fine immediately after RDO setup
 
Recreating external network, OVS bridge "br-ex"  and p37p1 as OVS port for "br-ex"

Reboot.
Openstack-status reports server errors

1.)
[root@openstack1 neutron(keystone_admin)]# nova  net-list
reports server error

2)
[root@openstack1 neutron(keystone_admin)]# nova  service-list
shows state  down every where

3)
/var/log/neutron/server.log.gz  is attached.

I believe to fix it , but it's just a hack

[boris@openstack1 ~]$ sudo su -
[sudo] password for boris:
Last login: Sun Jan 12 17:35:21 MSK 2014 on pts/0

[root@openstack1 ~]# ls -l /etc/neutron/neutron.conf
-rw-r-----. 1 root neutron 14386 Jan 12 16:15 /etc/neutron/neutron.conf

[root@openstack1 ~]# vi /etc/neutron/neutron.conf

Uncommented :

# Paste configuration file
api_paste_config = api-paste.ini

Updated /etc/rc.d/rc.local :-

[root@openstack1 neutron(keystone_admin)]# cat /etc/rc.d/rc.local
#!/bin/sh
losetup -f /var/lib/cinder/cinder-volumes && vgchange -a y cinder-volumes && systemctl restart openstack-cinder-volume.service
ifdown br-ex ;
ifup br-ex ;
service network restart ;
# Three times would be enough in general , but may be less
systemctl restart qpidd.service ;
systemctl restart qpidd.service ;
systemctl restart qpidd.service ;
service openstack-nova-compute restart ;
exit 0

Then in openstack-status report instead of server errors I get :-

[root@openstack1 neutron(keystone_admin)]# nova service-list
+------------------+------------------------+----------+---------+-------+----------------------------+-----------------+
| Binary           | Host                                       | Zone   | Status  | State | Updated_at  Disabled Reason |
+------------------+------------------------+----------+---------+-------+----------------------------+-----------------+
| nova-consoleauth | openstack1.localdomain | internal | enabled | up    | 2014-01-12T14:01:20.000000 | None            |
| nova-scheduler   | openstack1.localdomain  | internal | enabled | up    | 2014-01-12T14:01:20.000000 | None            |
| nova-conductor   | openstack1.localdomain | internal | enabled | up    | 2014-01-12T14:01:21.000000 | None            |
| nova-cert        | openstack1.localdomain      | internal | enabled | up    | 2014-01-12T14:01:20.000000 | None            |
| nova-compute     | openstack1.localdomain  | nova     | enabled | up    | 2014-01-12T14:01:19.000000 | None            |
+------------------+------------------------+----------+---------+-------+----------------------------+-----------------+
[root@openstack1 neutron(keystone_admin)]# nova  net-list
+--------------------------------------+---------+------+
| ID                                   | Label   | CIDR |
+--------------------------------------+---------+------+
| 54aa7248-072d-4d2d-a953-916894946c23 | private | None |
| d8760dfb-0619-4cd1-a033-51bb04eeb402 | public  | None |
+--------------------------------------+---------+------+


Neutron brought back to life

[root@openstack1 neutron(keystone_admin)]# neutron net-list
+--------------------------------------+---------+-----------------------------------------------------+
| id                                   | name    | subnets                                             |
+--------------------------------------+---------+-----------------------------------------------------+
| 54aa7248-072d-4d2d-a953-916894946c23 | private | ec123834-0cae-43b7-b85a-b6329dcc5e88 10.0.0.0/24    |
| d8760dfb-0619-4cd1-a033-51bb04eeb402 | public  | 87c37096-1186-4c67-8548-fb6c88839636 192.168.1.0/24 |
+--------------------------------------+---------+-----------------------------------------------------+
[root@openstack1 neutron(keystone_admin)]# neutron subnet-list
+--------------------------------------+----------------+----------------+--------------------------------------------------+
| id                                   | name           | cidr           | allocation_pools                                 |
+--------------------------------------+----------------+----------------+--------------------------------------------------+
| ec123834-0cae-43b7-b85a-b6329dcc5e88 | private_subnet | 10.0.0.0/24    | {"start": "10.0.0.2", "end": "10.0.0.254"}       |
| 87c37096-1186-4c67-8548-fb6c88839636 | public_subnet  | 192.168.1.0/24 | {"start": "192.168.1.57", "end": "192.168.1.97"} |
+--------------------------------------+----------------+----------------+--------------------------------------------------+

[root@openstack1 neutron(keystone_admin)]# ovs-vsctl show
d3454efb-b3d9-42d2-a277-913d5cf755fe
    Bridge br-ex
        Port br-ex
            Interface br-ex
                type: internal
        Port "qg-ce79686e-b8"
            Interface "qg-ce79686e-b8"
                type: internal
        Port "p37p1"
            Interface "p37p1"
    Bridge br-int
        Port "qvo10bf42f7-82"
            tag: 1
            Interface "qvo10bf42f7-82"
        Port "qr-01bdcf4b-05"
            tag: 1
            Interface "qr-01bdcf4b-05"
                type: internal
        Port "tapf8c3475f-f0"
            tag: 1
            Interface "tapf8c3475f-f0"
                type: internal
        Port br-int
            Interface br-int
                type: internal
        Port "qvofee768e5-64"
            tag: 1
            Interface "qvofee768e5-64"
    ovs_version: "2.0.0"