Fix urllib.parse (urlparse) handling

Revert "Fix "'module' object is not callable" error", and fix it properly.

* The urlparse module is renamed to urllib.parse in Python 3.
* This commit fixes the code to use "urllib.parse.urlparse"
  instead of creating a new module urlib and setting
  urlib.parse to urlparse.urlparse.
* Fixes an AttributeError:
  'function' object has no attribute 'uses_relative'

This reverts commit cd51f17c64.

Change-Id: I48490b20ecd19cf5a6edd835506ea5a467d556ac

manifest_xml.py

@@ -27,7 +27,7 @@ else:
   import imp
   import urlparse
   urllib = imp.new_module('urllib')
-  urllib.parse = urlparse.urlparse
+  urllib.parse = urlparse
 
 from git_config import GitConfig
 from git_refs import R_HEADS, HEAD