libstd: Fix missing export from URL module

Author: pcwalton

src/libstd/net_url.rs

@@ -1,6 +1,6 @@
 //! Types/fns concerning URLs (see RFC 3986)
 
-export url, userinfo, query, from_str, to_str;
+export url, userinfo, query, from_str, to_str, get_scheme;
 
 type url = {
     scheme: ~str,
@@ -236,4 +236,4 @@ mod tests {
         assert to_str(result::unwrap(from_str(url))) == url;
     }
 
-}
+}