vdsm.spec: fence-agents-all

fence-agents package in version 4 replaced the package name
to fence-agents-all. This patch will adapt vdsm spec to this change.

Change-Id: Ie4e92fda50aadb8223e721d72d43ea03b9b24f2d
Signed-off-by: Douglas Schilling Landgraf <dougsland@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/13249
Reviewed-by: Dan Kenigsberg <danken@redhat.com>