Fix default value for HostingService._http_request headers parameter
Review Request #4392 — Created Aug. 5, 2013 and submitted
Fix default value for HostingService._http_request headers parameter The default value for the 'headers' parameter to the _http_request was None, which meant that if something called it without passing in headers, urllib2.Request()'s constructor would throw an exception. Other similar code uses a default value of an empty dictionary, which is more appropriate.