heat scripts : Avoid using lsb_release in tools/openstack

lsb_release is not installed by default on Fedora (or at least
it's not on my F17 box), so we should avoid using it, simple
alternative is just to read /etc/fedora-release instead

Change-Id: I341c151e8560fb971b11d27578934940aeeca1a7
Signed-off-by: Steven Hardy <shardy@redhat.com>
Merge "heat scripts : Avoid using lsb_release in tools/openstack"