Tolerate responses with multiple Content-Length headers - fixes #196

--HG--
branch : distribute
extra : rebase_source : b0f0f73fd59017dd9a9bb6e58b2a1fd9e5773dd2

setuptools/package_index.py

@@ -579,7 +579,9 @@ class PackageIndex(Environment):
             bs = self.dl_blocksize
             size = -1
             if "content-length" in headers:
-                size = int(headers["Content-Length"])
+                # Some servers return multiple Content-Length headers :(
+                content_length = headers.getheaders("Content-Length")[0]
+                size = int(content_length)
                 self.reporthook(url, filename, blocknum, bs, size)
             tfp = open(filename,'wb')
             while True: