For SG-10538, bad certs on upload fix

This ensures we are using the right certificates when uploading a file.

Author: jfboismenu

shotgun_api3/shotgun.py

@@ -3102,7 +3102,8 @@ def _build_opener(self, handler):
         if self.config.proxy_handler:
             handlers.append(self.config.proxy_handler)
 
-        handlers.append(handler)
+        if handler is not None:
+            handlers.append(handler)
         return urllib2.build_opener(*handlers)
 
     def _turn_off_ssl_validation(self):
@@ -3810,7 +3811,7 @@ def _upload_data_to_storage(self, data, content_type, size, storage_url):
         :rtype: str
         """
         try:
-            opener = urllib2.build_opener(urllib2.HTTPHandler)
+            opener = self._build_opener(urllib2.HTTPHandler)
 
             request = urllib2.Request(storage_url, data=data)
             request.add_header("Content-Type", content_type)