Enable keystone_authtoken/memcach_use_advanced_pool for Sahara

Sahara was removed during Wallaby cycle and because of that it was not
updated when commit 09bcacd was
backported from Wallaby to Victoria.
This change updates the Sahara templates to have consistent definition
with the other services.

Related-Bug: #1931047
Change-Id: Idb9a209b2651c1ff03c3ccaa14f4976a9f267e99

deployment/deprecated/sahara/sahara-base.yaml

@@ -67,6 +67,11 @@ parameters:
     type: string
     default: 'regionOne'
     description: Keystone region for endpoint
+  MemcacheUseAdvancedPool:
+    type: boolean
+    description: |
+      Use the advanced (eventlet safe) memcached client pool.
+    default: true
 
 conditions:
   service_debug_unset: {equals : [{get_param: SaharaDebug}, '']}
@@ -118,3 +123,4 @@ outputs:
         sahara::keystone::authtoken::project_domain_name: 'Default'
         sahara::keystone::authtoken::region_name: {get_param: KeystoneRegion}
         sahara::keystone::authtoken::interface: 'internal'
+        sahara::keystone::authtoken::memcache_use_advanced_pool: {get_param: MemcacheUseAdvancedPool}