Enable aux-gfid-mount option on non Linux systems

The aux-gfid-mount works on non Linux systems, and it is required
to pass tests/basic/gfid-access.t

This is a backport of Ic6c8ef425e091440a139bbd25fadbf4f82e378cb

BUG: 1138897
Change-Id: Iab5487437fde65a66cff9cfeb7d209db7eb12108
Signed-off-by: Emmanuel Dreyfus <manu@netbsd.org>
Reviewed-on: http://review.gluster.org/8632
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>