Test if signal has attribute SIGQUIT

Add support for Windows users, since Windows doesn't support the SIGQUIT signal.

Author: johncmacy

django_dbq/management/commands/worker.py

@@ -84,7 +84,11 @@ def __init__(self, name, rate_limit_in_seconds):
 
     def init_signals(self):
         signal.signal(signal.SIGINT, self.shutdown)
-        signal.signal(signal.SIGQUIT, self.shutdown)
+        
+        # for Windows, which doesn't support the SIGQUIT signal
+        if hasattr(signal, "SIGQUIT"):
+            signal.signal(signal.SIGQUIT, self.shutdown)
+            
         signal.signal(signal.SIGTERM, self.shutdown)
 
     def shutdown(self, signum, frame):