Deprecate gluster_* modules (#1439)

* Deprecate gluster_* modules.

* Update 2.9 ignore.txt entries for deprecation syntax.

plugins/modules/storage/glusterfs/gluster_heal_info.py

@@ -11,6 +11,10 @@ DOCUMENTATION = '''
 ---
 module: gluster_heal_info
 short_description: Gather information on self-heal or rebalance status
+deprecated:
+    removed_in: 3.0.0
+    why: The gluster modules have migrated to the gluster.gluster collection.
+    alternative: Use M(gluster.gluster.gluster_heal_info) instead.
 author: "Devyani Kota (@devyanikota)"
 description:
   - Gather facts about either self-heal or rebalance status.

plugins/modules/storage/glusterfs/gluster_peer.py

@@ -14,6 +14,10 @@ DOCUMENTATION = '''
 ---
 module: gluster_peer
 short_description: Attach/Detach peers to/from the cluster
+deprecated:
+    removed_in: 3.0.0
+    why: The gluster modules have migrated to the gluster.gluster collection.
+    alternative: Use M(gluster.gluster.gluster_peer) instead.
 description:
   - Create or diminish a GlusterFS trusted storage pool. A set of nodes can be
     added into an existing trusted storage pool or a new storage pool can be

plugins/modules/storage/glusterfs/gluster_volume.py

@@ -10,6 +10,10 @@ __metaclass__ = type
 DOCUMENTATION = '''
 module: gluster_volume
 short_description: Manage GlusterFS volumes
+deprecated:
+    removed_in: 3.0.0
+    why: The gluster modules have migrated to the gluster.gluster collection.
+    alternative: Use M(gluster.gluster.gluster_volume) instead.
 description:
   - Create, remove, start, stop and tune GlusterFS volumes
 options: