gluster: remove unwanted error codes

This patch fixes to remove unwanted error codes which are no longer
needed.

Change-Id: I20284121a14b1e0f9f2d7c56c2f867eb71791bfd
Signed-off-by: Bala.FA <barumuga@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/19922
Reviewed-by: Timothy Asir <tjeyasin@redhat.com>
Reviewed-by: Dan Kenigsberg <danken@redhat.com>
Tested-by: Dan Kenigsberg <danken@redhat.com>