spec: remove shared glusterfs requirements

Since we now require glusterfs in the main package we can now remove the
same dependencies from the gluster rpm.

Change-Id: I6cdbf9a0bc97ce0bf42b0b7647a2641717442d58
Signed-off-by: Federico Simoncelli <fsimonce@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/18408
Reviewed-by: Deepak C Shetty <deepakcs@linux.vnet.ibm.com>
Reviewed-by: Douglas Schilling Landgraf <dougsland@redhat.com>
Reviewed-by: Allon Mureinik <amureini@redhat.com>
Reviewed-by: Dan Kenigsberg <danken@redhat.com>