fixed global variable reference when ssl verification is off (#230)

* fixed global variable reference when ssl verification is off

* moved 'global warned' to inside the function

gym/scoreboard/client/http_client.py

@@ -25,6 +25,7 @@ class RequestsClient(object):
         self.session = requests.Session()
 
     def request(self, method, url, headers, post_data=None, files=None):
+        global warned
         kwargs = {}
 
         # Really, really only turn this off while debugging.