gluster: Opening port 2049 for GlusterFS-NFS

The port 2049 should be open in iptables and that allows the volume to
be mounted

Change-Id: Ibc18874b337618e6bdd0a2151824c2765b52ee36
Bug-Url: https://bugzilla.redhat.com/979148
Signed-off-by: Shubhendu Tripathi <shtripat@redhat.com>