Fix use of http_proxy URLs without an explicit scheme. Fixes #238061.

--- lib/rubygems/remote_fetcher.rb.1	2008-06-21 23:21:17.000000000 +0200
+++ lib/rubygems/remote_fetcher.rb	2008-09-23 20:37:24.000000000 +0200
@@ -195,7 +195,7 @@
 
     return nil if env_proxy.nil? or env_proxy.empty?
 
-    uri = URI.parse env_proxy
+    uri = URI.parse(normalize_uri(env_proxy))
 
     if uri and uri.user.nil? and uri.password.nil? then
       # Probably we have http_proxy_* variables?