Wrong test in self-heal.t

self-heal.t checks for gfid before and after an operation, but fails
to do it on the same file since the prefix is not the same: undefined
$B1 before and $B0 after.

The errorcause the test to fail on NetBSD. I do not know how this test
could pass on Linux before.

BUG: 764655
Change-Id: I6df1175e177855afca1736cf8c847c51fe407576
Signed-off-by: Emmanuel Dreyfus <manu@netbsd.org>
Reviewed-on: http://review.gluster.org/8431
Reviewed-by: Ravishankar N <ravishankar@redhat.com>
Reviewed-by: Pranith Kumar Karampuri <pkarampu@redhat.com>
Tested-by: Pranith Kumar Karampuri <pkarampu@redhat.com>