Adding more information.

ONBOOT=yes[root@localhost ~]# ip addr

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default 

    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00

    inet 127.0.0.1/8 scope host lo

       valid_lft forever preferred_lft forever

    inet6 ::1/128 scope host 

       valid_lft forever preferred_lft forever

2: p5p1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000

    link/ether 00:22:41:28:14:20 brd ff:ff:ff:ff:ff:ff

    inet 192.168.5.151/24 brd 192.168.5.255 scope global dynamic p5p1

       valid_lft 85871sec preferred_lft 85871sec

    inet6 fe80::222:41ff:fe28:1420/64 scope link 

       valid_lft forever preferred_lft forever

3: ovs-system: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default 

    link/ether 22:4a:7f:81:49:15 brd ff:ff:ff:ff:ff:ff

4: br-ex: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default 

    link/ether 32:1a:96:7a:7e:4a brd ff:ff:ff:ff:ff:ff

    inet 192.168.5.151/24 brd 192.168.5.255 scope global br-ex

       valid_lft forever preferred_lft forever

    inet6 fe80::301a:96ff:fe7a:7e4a/64 scope link 

       valid_lft forever preferred_lft forever

8: br-int: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default 

    link/ether 32:99:19:54:f9:40 brd ff:ff:ff:ff:ff:ff

10: br-tun: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default 

    link/ether 76:49:ac:a6:ce:4f brd ff:ff:ff:ff:ff:ff

/etc/sysconfig/network-scripts/ifcfg-br-ex

[root@localhost ~]# cat /etc/sysconfig/network-scripts/ifcfg-br-ex

DEVICE=br-ex

DEVICETYPE=ovs

TYPE=OVSBridge

BOOTPROTO=static

IPADDR=192.168.5.151

NETMASK=255.255.255.0

ONBOOT=yes

[root@localhost ~]# cat /etc/sysconfig/network-scripts/ifcfg-p5p1

TYPE="OVSPort"

DEVICETYPE="ovs"

OVS_BRIDGE="br-ex"

DEFROUTE="yes"

IPV4_FAILURE_FATAL="no"

IPV6INIT="yes"

IPV6_AUTOCONF="yes"

IPV6_DEFROUTE="yes"

IPV6_PEERDNS="yes"

IPV6_PEERROUTES="yes"

IPV6_FAILURE_FATAL="no"

NAME="p5p1"

UUID="70997a7b-a01c-48a6-b961-b11304839108"

ONBOOT="yes"

HWADDR="00:22:41:28:14:20"

PEERDNS="yes"

PEERROUTES="yes"

Ran the following:

[root@localhost ~]# . keystonerc_admin 

[root@localhost ~(keystone_admin)]# neutron router-gateway-clear router1

Removed gateway from router router1

[root@localhost ~(keystone_admin)]# neutron subnet-delete public_subnet

Deleted subnet: public_subnet

[root@localhost ~(keystone_admin)]# neutron subnet-create --name public_subnet --enable_dhcp=False --allocation-pool=start=192.168.5.10,end=192.168.5.20 --gateway=192.168.5.1 public 192.168.5.0/24

Created a new subnet:

+-------------------+--------------------------------------------------+

| Field             | Value                                            |

+-------------------+--------------------------------------------------+

| allocation_pools  | {"start": "192.168.5.10", "end": "192.168.5.20"} |

| cidr              | 192.168.5.0/24                                   |

| dns_nameservers   |                                                  |

| enable_dhcp       | False                                            |

| gateway_ip        | 192.168.5.1                                      |

| host_routes       |                                                  |

| id                | 8f11b060-73a9-4b43-a3cc-be192436102c             |

| ip_version        | 4                                                |

| ipv6_address_mode |                                                  |

| ipv6_ra_mode      |                                                  |

| name              | public_subnet                                    |

| network_id        | 7fbe63c2-0745-45c3-9f00-622ee0eb223b             |

| tenant_id         | 636f926081a345fc93ca12fb5401ffe5                 |

+-------------------+--------------------------------------------------+

[root@localhost ~(keystone_admin)]#