features/glupy: Rename Glupy python module to avoid namespace conflict

* Rename gluster.py to glupy.py to avoid namespace conflict (#1018619)
* Move the main Glupy files into glusterfs-extra-xlators rpm
* Move the Glupy Translator examples into glusterfs-devel rpm

Backport of: http://review.gluster.org/#/c/6979/

Change-Id: Ie9b71b56502f8e98c527ade381c918446bc7f022
BUG: 1018619
Signed-off-by: Justin Clift <justin@gluster.org>
Reviewed-on: http://review.gluster.org/7316
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Kaleb KEITHLEY <kkeithle@redhat.com>
Reviewed-by: Jeff Darcy <jdarcy@redhat.com>