Fix broken NFS.

self.sdUUID does not exist when self.validateFileSystemFeatures
is called.

Broken by Icf14d1c4737.

Change-Id: Iabe379eb1c422ee21de0be2d21d9dea009d550ec
Signed-off-by: Eduardo <ewarszaw@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/11802
Tested-by: Yaniv Bronhaim <ybronhei@redhat.com>
Reviewed-by: Saggi Mizrahi <smizrahi@redhat.com>
Reviewed-by: Dan Kenigsberg <danken@redhat.com>