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

BUG: 764655
Change-Id: Ic6c8ef425e091440a139bbd25fadbf4f82e378cb
Signed-off-by: Emmanuel Dreyfus <manu@netbsd.org>
Reviewed-on: http://review.gluster.org/8446
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Humble Devassy Chirammal <humble.devassy@gmail.com>
Reviewed-by: Harshavardhana <harsha@harshavardhana.net>
Tested-by: Harshavardhana <harsha@harshavardhana.net>