add an Accept header to the http client

mercurial/httprepo.py

@@ -268,6 +268,7 b' class httprepository(repo.repository):'
 
         # 1.0 here is the _protocol_ version
         opener.addheaders = [('User-agent', 'mercurial/proto-1.0')]
+        opener.addheaders.append(('Accept', 'application/mercurial-0.1'))
         urllib2.install_opener(opener)
 
     def url(self):