Stop manila when unstacking

When you run unstack.sh from devstack, other devstack
services are stopped and disabled to provide a clean environment
for a restack, but manila services are left running.

This doesn't matter for CI where a new VM is stood up for each
devstack but it's inconvenient for local devstack and if you
restack without restarting the services manually the results you
see may not actually match the environment you intended.

Change-Id: I6761619042e4bc36ec2f1cab4be33cb1b39d00d7

devstack/plugin.sh

@@ -1324,10 +1324,12 @@ elif [[ "$1" == "stack" && "$2" == "test-config" ]]; then
 fi
 
 if [[ "$1" == "unstack" ]]; then
+    stop_manila
     cleanup_manila
 fi
 
 if [[ "$1" == "clean" ]]; then
+    stop_manila
     cleanup_manila
     sudo rm -rf /etc/manila
 fi