[Rdo-list] Devstack - why it uninstalls python-virtualenv?

When I'm installing DevStack, it performs the following: ++ FORCE_FIREWALLD=False ++ [[ rhel7 =~ (f20) ]] ++ uninstall_package python-virtualenv ++ is_ubuntu ++ [[ -z rpm ]] ++ '[' rpm = deb ']' ++ is_fedora ++ [[ -z CentOS ]] ++ '[' CentOS = Fedora ']' ++ '[' CentOS = 'Red Hat' ']' ++ '[' CentOS = CentOS ']' ++ sudo yum remove -y python-virtualenv Loaded plugins: fastestmirror, rhnplugin This system is receiving updates from RHN Classic or Red Hat Satellite. Resolving Dependencies --> Running transaction check ---> Package python-virtualenv.noarch 0:1.10.1-2.el7 will be erased --> Finished Dependency Resolution Dependencies Resolved ================================================================================ Package Arch Version Repository Size ================================================================================ Removing: python-virtualenv noarch 1.10.1-2.el7 @base 1.6 M Transaction Summary ================================================================================ Remove 1 Package Installed size: 1.6 M Downloading packages: Running transaction check Running transaction test Transaction test succeeded Running transaction Erasing : python-virtualenv-1.10.1-2.el7.noarch 1/1 Verifying : python-virtualenv-1.10.1-2.el7.noarch 1/1 Removed: python-virtualenv.noarch 0:1.10.1-2.el7 ... ++ pip_install virtualenv +++ set +o +++ grep xtrace ++ local 'xtrace=set -o xtrace' ++ set +o xtrace ++ sudo -H http_proxy= https_proxy= no_proxy= /bin/pip install virtualenv Requirement already satisfied (use --upgrade to upgrade): virtualenv in /usr/lib/python2.7/site-packages ... Only to complain later: +++ mktemp -d tmp-venv-XXXX ++ TMP_VENV_PATH=tmp-venv-uUwo ++ virtualenv tmp-venv-uUwo /opt/stack/tools/build_wheels.sh: line 57: virtualenv: command not found +++ err_trap WHAAAAT? Y.