Revert "Leave initialization in c'tor, just call start() where needed"

This reverts commit d41ceabe82. Which I suspect
does not work because the thread is stateful, i.e. after os.fork the thread in
copy of the process thinks it has already been started, even though it is not
alive. Probably safest to just get a new thread instance if a thread is not alive.

logzio/sender.py

@@ -34,15 +34,19 @@ class LogzioSender:
 
         # Create a queue to hold logs
         self.queue = queue.Queue()
+        self._initialize_sending_thread()
+
+    def _initialize_sending_thread(self):
         self.sending_thread = Thread(target=self._drain_queue)
         self.sending_thread.daemon = False
         self.sending_thread.name = "logzio-sending-thread"
         self.sending_thread.start()
 
     def append(self, logs_message):
-        # Queue lib is thread safe, no issue here
         if not self.sending_thread.is_alive():
-            self.sending_thread.start()
+            self._initialize_sending_thread()
+
+        # Queue lib is thread safe, no issue here
         self.queue.put(json.dumps(logs_message))
 
     def flush(self):