Caps: Include glusterfs packages

Updated getVdsCaps verb to provide glusterfs package info along with
other key package details.

Change-Id: I38991550e57c8f1e558f297cf12d984f7f0bc635
Signed-off-by: Timothy Asir <tjeyasin@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/11138
Reviewed-by: Dan Kenigsberg <danken@redhat.com>