Add errornous shutdown logging

src/de/steamwar/bungeecore/Subserver.java

@@ -140,8 +140,10 @@ public class Subserver {
         }
 
         try {
-            if(!process.waitFor(1, TimeUnit.MINUTES))
+            if(!process.waitFor(1, TimeUnit.MINUTES)) {
+                logger.log(Level.SEVERE, () -> serverName + " did not stop correctly, forcibly stopping!");
                 process.destroyForcibly();
+            }
 
             thread.join();
         }catch(InterruptedException e){