Sync log from oslo-incubator for isEnabledFor fix

Sync log.py to get commit:

726d00a Adjust oslo logging to provide adapter is enabled for

Which is needed to fix an issue with logging in flow_utils
when using python 2.6.

This also brings in dependencies.

Changes:

jsonutils
---------
ef37e03 Added missing jsonutils.dump() function

log
---
726d00a Adjust oslo logging to provide adapter is enabled for
433fa0b Make logging_context_format_string optional in log.set_defaults
ac92c06 Add default log level for websocket
5fd77eb Ability to customize default_log_levels for each project
4d9328c Python 3: enable tests/unit/test_log.py
cb5a804 Move `mask_password` to strutils
3310d8d update new requests logger to default WARN

strutils
--------
cb5a804 Move `mask_password` to strutils

Change-Id: Iea344e4bd3a612cd4110143e4fbb8e2fdfd88165
Closes-Bug: #1343544
Merge "Sync log from oslo-incubator for isEnabledFor fix"