vfs:glusterfs_fuse: ensure fileids are constant across nodes

vfs:glusterfs_fuse: ensure fileids are constant across nodes

Instead of adding a new gluster-specific mode to the fileid module,
this patches provides a fileid algorithm as part of the glusterfs_fuse
vfs module. This can not be configured further, simply adding the
glusterfs_fuse vfs module to the vfs objects configuration will enable
the new fileid mode.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=13972

Signed-off-by: Michael Adam <obnox@samba.org>
Signed-off-by: Guenther Deschner <gd@samba.org>