SYN-395: Fix CAPTCHA, don't double decode json

synapse/handlers/auth.py

@@ -187,7 +187,7 @@ class AuthHandler(BaseHandler):
         # each request
         try:
             client = SimpleHttpClient(self.hs)
-            data = yield client.post_urlencoded_get_json(
+            resp_body = yield client.post_urlencoded_get_json(
                 "https://www.google.com/recaptcha/api/siteverify",
                 args={
                     'secret': self.hs.config.recaptcha_private_key,
@@ -199,6 +199,7 @@ class AuthHandler(BaseHandler):
             # Twisted is silly
             data = pde.response
             resp_body = simplejson.loads(data)
+
         if 'success' in resp_body and resp_body['success']:
             defer.returnValue(True)
         raise LoginError(401, "", errcode=Codes.UNAUTHORIZED)