Fix auth_url in metadata_agent.ini

Closes-Bug: #1214921

The value of auth_url is incorrect, some operators may not change
that value and problem will occur. According to keystone, 35357 is
the port number which the public admin listens on, 5000 should be
used for neutron instead.

Change-Id: I0b35f25c1845d02f8b9b3cd8c759920d52003c0c
Merge "Fix auth_url in metadata_agent.ini"