cyclades: Do not allow any action on 'ERROR' vms

Do not allow any action, other than 'DESTROY' in servers that are in
'ERROR' state. If the server is in 'ERROR' state then the corresponding
Ganeti instance may not exist, so all actions will fail.

snf-cyclades-app/synnefo/logic/servers.py

@@ -40,7 +40,10 @@ def validate_server_action(vm, action):
 
     # Check if action can be performed to VM's operstate
     operstate = vm.operstate
-    if operstate == "BUILD" and action != "BUILD":
+    if operstate == "ERROR":
+        raise faults.BadRequest("Can not perform '%s' action while server is"
+                                " in 'ERROR' state." % action)
+    elif operstate == "BUILD" and action != "BUILD":
         raise faults.BuildInProgress("Server '%s' is being build." % vm.id)
     elif (action == "START" and operstate != "STOPPED") or\
          (action == "STOP" and operstate != "STARTED") or\