hgweb: remove wsgirequest.__iter__

This was added in d0db3462d568 in 2006. I can't find a justification
for this method in PEP 3333. I suspect we were originally intending
to use this type as the WSGI application (which should be iterable)?

The tests all pass without this method. So let's nuke it.

Differential Revision: https://phab.mercurial-scm.org/D2749

mercurial/hgweb/request.py

@@ -246,9 +246,6 class wsgirequest(object):
         self.server_write = None
         self.headers = []
 
-    def __iter__(self):
-        return iter([])
-
     def drain(self):
         '''need to read all data from request, httplib is half-duplex'''
         length = int(self.env.get('CONTENT_LENGTH') or 0)