Update db.sqlalchemy.session from oslo-incubator 018138

Keystone's db.sqlalchemy.session module was out of date. This
updates Keystone's version to oslo-incubator hash
01813871e2f6b9b01783f7da88998d9bc97d4a8c .

 $ python update.py --nodeps --base keystone \
    --dest-dir ../keystone --modules db.sqlalchemy.session

Among other changes, the newer db.sqlalchemy.session has fixes to
the docstring so there are fewer warnings issued during doc build
and rendering issues.

Change-Id: I70f6727adeb98142f8a9a1cea04c71ade27dfaba
Remove tox locale overrides

* tox.ini: The LANG, LANGUAGE and LC_ALL environment overrides were
introduced originally during the testr migration in an attempt to be
conservative about the possibility that locale settings in the
calling environment could cause consistency problems for test runs.
In actuality, this should be unnecessary and any place where it does
cause issues ought to be considered an actual bug. Also, having
these in the configuration actively causes older pip to have
problems with non-ASCII content in some package metadata files under
Python 3, so drop it now.

Change-Id: Icf41e4e7a869375e9be710f42c7dd05f9daf100b
Closes-Bug: #1277495
Merge "Remove tox locale overrides"
Merge "Update db.sqlalchemy.session from oslo-incubator 018138"