Use oslo network utils function to set tcp_keepalive

Earlier, tcp_keepidle was set to 600s and other parameters left to default
values. A new function was added to oslo-incubator for setting tcp keepalive
settings, and cinder should use this to set any values we want.
In addition to the existing cfg option for tcp_keepidle, new values were added
for tcp_keepalive(to turn on/off this feature, tcp_keepintvl(to specify gap
between successive probes) and tcp_keepcnt(to specify number of probes). To
mimic existing behavior, tcp_keepalive defaults to True, and tcp_keepidle to
600(seconds). The other two default to None, and the oslo code will ignore
them.
Ran update.py in oslo-incubator to copy changed modules into cinder.
Changes are:
network_utils.py (which contains the function we need, others are deps)
edd73c9 Merge "Improve help strings"
fe3389e Improve help strings
8a0f567 Remove str() from LOG.* and exceptions
f61a4e7 Fix python26 compatibility for RFCSysLogHandler
da6d713 Revert setting oslo-incubator logs to INFO
0d18381 Set default log levels for oslo.messaging and oslo-incubator

gettextutils.py
9912e5d Add API for creating translation functions
6cc96d0 Fix test_gettextutils on Python 3

jsonutils.py
9e5a393 jsonutils.load() accepts file pointer, not string
a6b2aec On Python <= 2.6, use simplejson if available
e3a1d9c Use six.moves.xmlrpc_client instead of xmlrpclib
3a31bba Python3 support for xmlrpclib
e6494c2 Use six.iteritems to make dict work on Python2/3

log.py
edd73c9 Merge "Improve help strings"
fe3389e Improve help strings
8a0f567 Remove str() from LOG.* and exceptions
f61a4e7 Fix python26 compatibility for RFCSysLogHandler
da6d713 Revert setting oslo-incubator logs to INFO
0d18381 Set default log levels for oslo.messaging and oslo-incubator

Current HEAD in OSLO:
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Merge: 2640847 e433899
Date:   Mon May 5 19:41:28 2014 +0000
Merge "Enable configuring tcp keepalive"
----------------------------------------------

Ran generate_sample to generate cinder.conf.sample

Implements blueprint configure-tcp-keepalive
Change-Id: I2e4c2327803c25e54ed771f25ef973bb543b9355
Removes unecessary call to rbd.Image

Removed duplicate and unprotected call to rbd.Image
in rbd driver which can result in an uncaught exception
if the rbd image no longer exists.

Also added unit test for _delete_backup_snaps()

Closes-Bug: 1323203
Change-Id: I89eedb0d0276a985b4d496093df2eee2ce067ec1
Made provision for providing optional arguments

The 'quota_committed' attribute of 'RequestContext' object is
a transient property, so it will not be saved in the taskflow
persistent storage. The updated value of 'quota_committed'
attribute will not be available while resuming/reverting the
flow, if cinder api-service is down/stopped after committing
the quota.

Since this 'quota_committed' attribute is not used anywhere
in cinder project other than in create-volume taskflow api, so
removed 'quota_committed' from RequestContext and made
provision to pass it as an optional argument which will be
passed to api-flow via create_what dictionary, in order to
make it persistent and use it as and when needed.

Change-Id: I719067a8e1824add45fb525c106642a9c0e6bb46
Merge "Use oslo network utils function to set tcp_keepalive"
Merge "Made provision for providing optional arguments"