Merge with Oslo (master/ded9bd6)

Merges with current master of oslo-incubator, which brings
in several Python 3.x and other code fixes:

    ded9bd6  Make dependency on netaddr optional
    c331e74  Enable multiple translation domains for gettextutils
    17df920  Allow mapping _ to lazy gettext path
    ed653bf  Fix Message format-string parsing
    3198881  Add common methods required to allow translation of REST API responses
    df3f2ba  BaseException.message is deprecated since Python 2.6
    79ee367  Add more robust gettext interpolation handling
    45e0cbe  python3: Add basic python3 compatibility.
    1a2df89  Enable H302 hacking check
    d28fa69  python3: Add python3 compatibility.
    7b7566b  Add netaddr.IPAddress support to to_primitive()
    67bd769  python3: Fix traceback while running python3.
    b0c51ec  Refactors to_bytes
    472d8ed  Add slugify to strutils
    7119e29  Enable hacking H404 test.
    4246ce0  Added common code into fileutils and strutils.
    e3545f8  Enable hacking H402 test
    484a1df  Enable hacking H403 test
    50cae76  Add basic lazy gettext implementation
    536c39e  Add 't', 'y', and `strict` to `bool_from_string`
    d9b0719  Handle ints passed to `boolean_from_string`
    fde1e15  Convert unicode for python3 portability
    8c964a2  Do not import openstack.common.log in strutils
    9dcf688  Optimise to_primitive common cases
    e700d92  Replaces standard logging with common logging
    c8f676b  Support overriding oslo localedir too
    d8b66c7  Add a gettextutils.install() helper function
    f75126c  gettextutils: fix translation domain
    547ab34  Fix Copyright Headers - Rename LLC to Foundation
    2cb8e45  support ISO 8601 micro-second precision
    4eae556  Don't LOG.error on max_depth (by default).
    bd5dad9  Decode / Encode string utils for openstack
    a94b9b4  to_primitive imposes what seems to be an arbitary data structure
    a878193  Allow to_primitive to ignore datetimes
    1461135  timeutils: considers that now is soon
    a956f7a  Import timeutils.is_soon from keystoneclient
    d3a4c8e  UTC ISO8601 from timestamp
    33b12d3  Implement importutils.try_import.
    a08daf1  Use basestring instead of str for type check.

Change-Id: I7dc12e23ba89b74a3beeb49c24986110bd1682c6
Merge "Merge with Oslo (master/ded9bd6)"