[netinstall] The status is ready (done) when the queue is done

- Don't signal ready every time data is sent to the model, since
  if the model ends up empty, loading will continue with the next
  fallback entry.

src/modules/netinstall/Config.cpp

@@ -97,7 +97,6 @@ Config::loadGroupList( const QVariantList& groupData )
     {
         setStatus( Status::Ok );
     }
-    emit statusReady();
 }
 
 void
@@ -108,6 +107,7 @@ Config::loadingDone()
         m_queue->deleteLater();
         m_queue = nullptr;
     }
+    emit statusReady();
 }