Add py3kcompat utils module

It's needed for the updated oslo.db code.
Currently it only provides urlutils.

Change-Id: Ieb25716930537a26e74d714db04678c7b81143cb
Sync minor updates in oslo.db module

* vim headers removed
* py3kcompat/urlutils functions used instead of urlparse
* log.warning() used instead of log.warn()
* license, typos and docstrings fixed
* locking fixed

Change-Id: I2a9bfc04ae473220da39cdf723247deba87dc07b
Merge "Add py3kcompat utils module"
Merge "Sync minor updates in oslo.db module"