Updated openstack/openstack
Project: openstack-dev/devstack  e9b343c3c973cb5e23d85e6dac956824c41ca834

[Fedora] Devstack fails to install in firewalld less system

The official F20 cloud image does not contains the firewalld,
there is nothing to restart, and it fails the installation.

The previous workaround change, assumed all is_fedoras has
a restartable firewalld without ensuring is it installed at all.

RHEL6 even does not have a firewalld.

Closes-bug: #1329102
Change-Id: I3d119ce48af81b30bf02b01c2cd386612ac6ef90