Convert explicit session get/begin to transaction context

Convert the explicit common.sql.get_session() and subsequent
session.begin() to the transaction context manager for Trust
SQL backend.

Change-Id: I52745118782301ef26452063628e16e92e8ee276
Regenerate sample config file

The sample config file was regenerated using

 tox -r -e sample_config

Change-Id: I2e0b12369742b9fbe2ec97725e8771af64f2b2a5
Do not log 14+ INFO lines on a broken pipe error (eventlet)

Under eventlet if the client disconnects while Keystone is trying
to transmit data, approximately 14 lines of traceback are logged.

This could result in massive logs if done repeatedly; worst case
scenario could include a denial of service due to disk space being
exhausted.

Change-Id: Iaf14c64799daa7539d1bd85cb6c6457380c111d9
Closes-Bug: #1334466
Imported Translations from Transifex

Change-Id: I8bdb9ecd6bf8e88670c08e938dae71eabd989d55
Adds oslo.db support for Python 3 tests

bp python3

Change-Id: I0c1cf795c82760aa7ccbce010afca7533b351541
Merge "Convert explicit session get/begin to transaction context"
Merge "Do not log 14+ INFO lines on a broken pipe error (eventlet)"
Merge "Adds oslo.db support for Python 3 tests"
Merge "Regenerate sample config file"