Clean up local variable usage - Backends

Combines cleanup for mysql, postgresql and rpc

Change-Id: I37b928a669146671c946fc1ccb8e3ef1a27a3891

lib/rpc_backend

@@ -26,6 +26,8 @@ set +o xtrace
 # Make sure we only have one rpc backend enabled.
 # Also check the specified rpc backend is available on your platform.
 function check_rpc_backend {
+    local c svc
+
     local rpc_needed=1
     # We rely on the fact that filenames in lib/* match the service names
     # that can be passed as arguments to is_service_enabled.
@@ -138,6 +140,7 @@ function restart_rpc_backend {
         # NOTE(bnemec): Retry initial rabbitmq configuration to deal with
         # the fact that sometimes it fails to start properly.
         # Reference: https://bugzilla.redhat.com/show_bug.cgi?id=1059028
+        local i
         for i in `seq 10`; do
             if is_fedora || is_suse; then
                 # service is not started by default