pywsgi: stop processing requests if self.socket is set to None

this is needed for websocket which needs to own the connection

gevent/pywsgi.py

@@ -158,7 +158,7 @@ class WSGIHandler(object):
 
     def handle(self):
         try:
-            while True:
+            while self.socket is not None:
                 self.time_start = time.time()
                 self.time_finish = 0
                 result = self.handle_one_request()
@@ -173,6 +173,7 @@ class WSGIHandler(object):
                 self.log_request()
                 break
         finally:
+            if self.socket is not None:
                 try:
                     self.socket._sock.close()  # do not rely on garbage collection
                     self.socket.close()