Presently it's impossible to use httplib.HTTPConnection.request and send 
the several headers with the same name. This is because _send_request 
assumes a dict is passed in, or a dict-like interface. Obviously one could 
make a list subclass or some such and give it an iteritems that returns 
itself, but IMHO the solution is to fix httplib.

Attached patch changes the current behavior to using iteritems only if it 
exists, otherwise iterate directly (which would fit with sequences of two-
tuples).