island: Log a warning if MongoDbProcess.stop() is erroniously called

monkey/monkey_island/cc/setup/mongo/mongo_db_process.py

@@ -36,9 +36,13 @@ class MongoDbProcess:
         logger.info("MongoDB launched successfully!")
 
     def stop(self):
-        if self._process:
+        if not self._process:
+            logger.warning("Failed to stop MongoDB process: No process found")
+            return
+
         logger.info("Terminating MongoDB process")
         self._process.terminate()
+
         try:
             self._process.wait(timeout=TERMINATE_TIMEOUT)
             logger.info("MongoDB process terminated successfully")