Merge "Join command thread on exit"

zuul/executor/server.py

@@ -2812,6 +2812,7 @@ class ExecutorServer(BaseMergeServer):
         if self.process_merge_jobs:
             super().join()
         self.executor_gearworker.join()
+        self.command_thread.join()
 
     def pause(self):
         self.log.debug('Pausing')

zuul/lib/fingergw.py

@@ -217,3 +217,6 @@ class FingerGateway(object):
         Wait on the gateway to shutdown.
         '''
         self.server_thread.join()
+
+        if self.command_thread:
+            self.command_thread.join()