Include url in warning when processing URL. Fixes #135.

--HG--
branch : distribute
extra : rebase_source : 1241e1cb548adad562fcf61ce33538712a64aaed

setuptools/package_index.py

@@ -198,7 +198,7 @@ class PackageIndex(Environment):
             return
 
         self.info("Reading %s", url)
-        f = self.open_url(url, "Download error: %s -- Some packages may not be found!")
+        f = self.open_url(url, "Download error on %s: %%s -- Some packages may not be found!" % url)
         if f is None: return
         self.fetched_urls[url] = self.fetched_urls[f.url] = True