glusterd: op-version check for brickops.

cluster op-version must be atleast 4 for add/remove brick to proceed.
This change is required for the new afr-changelog xattr changes that
will be done for glusterFS 3.6 (http://review.gluster.org/#/c/7155/).

In add-brick, the check is done only when replica count is increased
because only that will affect the AFR xattrs.

In remove-brick, the check is unconditional failing which there will be
inconsistencies in the client xlator names amongst the volfiles of
different peers.

Change-Id: If981da2f33899aed585ab70bb11c09a093c9d8e6
BUG: 1066778
Signed-off-by: Ravishankar N <ravishankar@redhat.com>
Reviewed-on: http://review.gluster.org/7122
Reviewed-by: Kaushal M <kaushal@redhat.com>
Reviewed-by: Pranith Kumar Karampuri <pkarampu@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>
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
* Add Glupy entry to the MAINTAINERS file

BUG: 1018619
Change-Id: I48de598ba5ae8eec0e7e276bbcca1abb0e549cef
Signed-off-by: Justin Clift <justin@gluster.org>
Reviewed-on: http://review.gluster.org/6979
Reviewed-by: Kaleb KEITHLEY <kkeithle@redhat.com>
Reviewed-by: Jeff Darcy <jdarcy@redhat.com>
features/compress: Add mem accounting support for compress

Change-Id: I89a7a4cd64ef65ad3bab180d66797a62b4e1e195
BUG: 923540
Signed-off-by: Pranith Kumar K <pkarampu@redhat.com>
Reviewed-on: http://review.gluster.org/7320
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Prashanth Pai <ppai@redhat.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>