Pull latest service module from Oslo

Get latest service module from Oslo to prepare for multi-process API service implementation.
Below are the commits included in this pull.

Changes being pulled into in service module are:
* e7bc8c9 2013-11-20 | Merge "os._exit in _start_child may cause unexpected exception"
* 96a2d4e 2013-11-07 | os._exit in _start_child may cause unexpected exception
* 1771a77 2013-11-05 | Adjust import order according to PEP8 imports rule
* 3110c0f 2013-10-17 | Use multiprocessing.Event to ensure services have started
* b5fba9e 2013-09-18 | Move comment in service.py to correct location
* 11cc74f 2013-08-26 | Fixes issue with SUGHUP in services on Windows
* 825ace5 2013-06-17 | Add service restart function in oslo-incubator
* c935d1c 2013-07-16 | Merge "Allow launchers to be stopped multiple times"
* dc8aa79 2013-07-08 | Allow launchers to be stopped multiple times
* 1a2df89 2013-06-25 | Enable H302 hacking check
* 52e857a 2013-06-19 | Ignore any exceptions from rpc.cleanup().
* 5518ad3 2013-05-16 | Add graceful service shutdown support to Launcher

And these dependent modules
 - cinder/openstack/common/eventlet_backdoor.py
    * 1dcc747 2013-07-15 | Fix stylistic problems with help text
    * 1a2df89 2013-06-25 | Enable H302 hacking check
    * c7c55b2 2013-06-20 | Improve usability when backdoor_port is nonzero
 - cinder/openstack/common/gettextutils.py
    * 3970d46 2013-11-02 | Fix typos in oslo
    * 88db9c8 2013-10-03 | When translating if no locale is given use default locale
 - cinder/openstack/common/jsonutils.py
    * 3d7504b 2013-09-23 | Ensure that Message objects will be sent via RPC in unicode format
    * 1807d32 2013-08-22 | jsonutils: make types py3 compatible
    * bdef862 2013-08-22 | jsonutils: do not require xmlrpclib
    * ded9bd6 2013-08-04 | Make dependency on netaddr optional
    * 7b7566b 2013-06-25 | Add netaddr.IPAddress support to to_primitive()
 - cinder/openstack/common/local.py
    * cb2a2b6 2013-06-28 | Modify local.py to not be dependent on Eventlet
    * 547ab34 2013-03-11 | Fix Copyright Headers - Rename LLC to Foundation
 - cinder/openstack/common/log.py
    * a82e889 2013-11-14 | Merge "Do not name variables as builtins"
    * 2251cb5 2013-11-13 | Do not name variables as builtins
    * 25c5854 2013-11-13 | Adds admin_password as key to be sanitized when logging
    * cbfded9 2013-11-11 | Default iso8601 logging to WARN
    * 76b0cd1 2013-11-04 | Add mask password impl from other projects
 - cinder/openstack/common/loopingcall.py
    * 1a2df89 2013-06-25 | Enable H302 hacking check
 - cinder/openstack/common/threadgroup.py
    * 9d3c34b 2013-10-25 | Add a link method to Thread
    * 1a2df89 2013-06-25 | Enable H302 hacking check
 - cinder/openstack/common/timeutils.py
    * f3b5f17 2013-11-12 | Add helper method total_seconds in timeutils.py
    * 53ebd30 2013-10-18 | python3: use six.text_types for unicode()
    * 3bc6f79 2013-09-19 | Fix timeutils.set_override_time not defaulting to current wall time
    * af76064 2013-08-29 | Optimize timeutils.utcnow_ts()
    * df3f2ba 2013-07-26 | BaseException.message is deprecated since Python 2.6
    * d28fa69 2013-06-27 | python3: Add python3 compatibility.

Partial bp: multi-process-api-service

Change-Id: Ifd25eae9eb2d6ae53bcf1665c3d5b7db4144433c
Fix docstring for Snapshot model

"Represents a block storage device that can be attached to a VM." as the
description of model Snapshot is incorrect.

Change-Id: I1d7c985869f0829b9305a18a3570928a9da40519
Closes-Bug: #1254635
Merge "Pull latest service module from Oslo"
Merge "Fix docstring for Snapshot model"