auth: fix realm handling with Python < 2.4.3 (issue2739)

mercurial/httpconnection.py

@@ -70,7 +70,11 b' def readauthforuri(ui, uri, user):'
         gdict[setting] = val
 
     # Find the best match
-    scheme, hostpath = uri.split('://', 1)
+    if '://' in uri:
+        scheme, hostpath = uri.split('://', 1)
+    else:
+        # py2.4.1 doesn't provide the full URI
+        scheme, hostpath = 'http', uri
     bestuser = None
     bestlen = 0
     bestauth = None