Sync log.py from oslo-incubator

Sync log.py from oslo-incubator

This pulls in the latest version of log.py from oslo-incubator
which elminates the constant user_identity key error.

Note that this sync does a full sync, in other words it uses
the oslo update script and pulls in the log.py file and all
of the associated dependendencies for that module.

Current HEAD in OSLO:
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Merge: d9ea4f0 fd33d1e
Date:   Wed Mar 12 17:00:13 2014 +0000
Merge "Fix gettextutil.Message handling of deep copy failures"
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Change-Id: I7c9f8acd22787f9649a5a1e796238c7788a0484a
Fixes-Bug: 1290503