Partial oslo-incubator sync

Generated with:
python update.py --base nova --dest-dir ~/Develop/tmp/nova/ --modules
timeutils,sslutils,importutils,memorycache,strutils,context,fileutils,versionutils,systemd

context:
 9b73877 Add a RequestContext.from_dict method
 85d1ce6 Python 3: enable tests/unit/middleware/test_request_id.py
fileutils:
  2b966f9 Fix deletion of cached file for policy enforcer
gettextutils:
 3d90045 Backport code for i18n to check lazy at runtime
jsonutils:
 ef37e03 Added missing jsonutils.dump() function
log:
 5cac11d Merge "Add default log level for websocket"
 433fa0b Make logging_context_format_string optional in log.set_defaults
 ac92c06 Add default log level for websocket
 0aa2bd4 Merge "Ability to customize default_log_levels for each project"
 5fd77eb Ability to customize default_log_levels for each project
 i4d9328c Python 3: enable tests/unit/test_log.py
 722f418 Merge "update new requests logger to default WARN"
 cb5a804 Move `mask_password` to strutils
memorycache:
 90ae24b Remove redundant default=None for config options
 297d772 Raise exception when importing memcache error
strutils:
 cb5a804 Move `mask_password` to strutils
systemd:
 17c4e21 Fix docstring indentation in systemd
 667d1ba Fixed spelling error - occured to occurred
versionutils:
 a2ad3a2 Allow deprecated decorator to specify no plan for removal
 05ae498 Add JUNO as a target to versionutils module

Change-Id: I9e8e8e9b15075d99cf394170c6f5300e7bd0d4cc
Merge "Partial oslo-incubator sync"