Fix manila backend_names and enable_protocols

A backend in manila can have multiple storage pools
and capabilities for each pool are considered to
create configuration for tempest tests. These
capabilities however may overlap with each other,
so we need some de-duplication.

Change-Id: I108615ab197b8959fe944e21ae7c1a36125ca531

config_tempest/services/share.py

@@ -44,12 +44,12 @@ class ShareService(VersionedService):
                           "pools - storage back-ends can't be discovered.")
             return
         if pools:
-            backends = []
-            enable_protocols = []
+            backends = set()
+            enable_protocols = set()
             for pool in pools:
-                backends.append(pool['backend'])
+                backends.add(pool['backend'])
                 protocol = pool['capabilities']['storage_protocol'].lower()
-                enable_protocols.extend(protocol.split('_'))
+                enable_protocols.update(protocol.split('_'))
 
             conf.set('share', 'backend_names', ','.join(backends))
             conf.set('share', 'enable_protocols', ','.join(enable_protocols))