hgweb: more native string treatment in query string parsing

Differential Revision: https://phab.mercurial-scm.org/D1076

mercurial/hgweb/server.py

@@ -37,10 +37,10 b' def _splitURI(uri):'
     Just like CGI environment, the path is unquoted, the query is
     not.
     """
-    if '?' in uri:
-        path, query = uri.split('?', 1)
+    if r'?' in uri:
+        path, query = uri.split(r'?', 1)
     else:
-        path, query = uri, ''
+        path, query = uri, r''
     return urlreq.unquote(path), query
 
 class _error_logger(object):