postcreate.sh: add Fedora 20+

... so those extended attributes are correctly set.

Signed-off-by: Kir Kolyshkin <kir@openvz.org>
postcreate.sh: set file caps for suse 13.1+

Apparently suse 13.1 also start to use security attributes, so
set it.

Signed-off-by: Kir Kolyshkin <kir@openvz.org>