Fixes errors when nova is disabled

This patch checks if nova is disabled in some
plugins so we can run packstack with
CONFIG_NOVA_INSTALL=n

Added also an ALL option to the firewall
template.

Change-Id: I05a9bd55c89d4009e28307248d74624533d47240
Fixes: rhbz#987888 rhbz#1024564 rhbz#1026795
Merge "Fixes errors when nova is disabled"