Mails: properly pop eaten item even if the server is not started

This fixes ThreadedSMTP.quit() when the connection to the server is
down as Queue.join() will wait for all tasks to be popped and accounted
for, but we wouldn't account for the fake (empty) task because the
connection to the server would not be open.

So, properly differentiate a closed connection from a queue timeout.

lib/mails.py

@@ -43,10 +43,12 @@ class ThreadedSMTP(object):
 
         server = None
         while self._loop or not self._queue.empty():
+            task_eaten = True
             try:
                 args, kwargs = self._queue.get(timeout=timeout)
             except queue.Empty:
                 server = self.__server_quit(server)
+                task_eaten = False  # we didn't eat a task, just timeout
             except KeyboardInterrupt as e:
                 break
             else:
@@ -58,7 +60,7 @@ class ThreadedSMTP(object):
                     except Exception as e:
                         logging.warning("Couldn't send email: %s" % str(e))
             finally:
-                if server:  # server is None on exception queue.Empty
+                if task_eaten:
                     self._queue.task_done()
         self.__server_quit(server)