Fixing middleware servers alert handling

* miq_alert: MiddlewareServers model has STI enabled. It's not
  enough to test against the class name to detect if target
  is a mw-server. Using kind_of?.
* middleware_server: The format of the alert ids changed.
  Testing against the new id format in addition to the old
  one to check if alert should be handled.

app/models/middleware_server.rb

@@ -33,7 +33,8 @@ def evaluate_alert(alert_id, event)
     s_start = event.full_data.index("id=\"") + 4
     s_end = event.full_data.index("\"", s_start + 4) - 1
     event_id = event.full_data[s_start..s_end]
-    if event_id.start_with?("MiQ-#{alert_id}") && event.middleware_server_id == id
+    if event.middleware_server_id == id && (
+      event_id.start_with?("MiQ-#{alert_id}") || event_id.start_with?(ext_management_system.miq_id_prefix))
       return true
     end
     false

app/models/miq_alert.rb

@@ -586,7 +586,7 @@ def evaluate_in_automate(target, inputs = {})
   end
 
   def evaluate_internal(target, _inputs = {})
-    if target.class.name == 'MiddlewareServer'
+    if target.kind_of?(::MiddlewareServer)
       method = "evaluate_middleware"
       options = _inputs[:ems_event]
     else