Fix variable typo of use_syslog in lib/tempest

TEMPEST_CONF is not set but used it. As a result the meaningless file
'DEFAULT' is created. So this commit fixes to use proper variable name.

Closes-bug: #1394969
Change-Id: If6e58f269319df3c4f71b4fc13aa855c63f7e3a3
Update devstack to work with new split neutron services repos

This commit udpates devstack to work with the latest neutron services, which
are now in their own repositories. This will also unblock third party CI for
services testing. This also allows devstack users to run neutron with
services again.

Change-Id: I9cdd51f09edaccf218988240b48ce733d5771a65
Add tooz support from Oslo

Change-Id: I4ccf4bf08e10c0ba651f973aa62562af85ea0f19
Tempest: configure exact set of extensions to test

So far devstack configures tempest either for testing all extensions
or a specific subset. It does not allow users for specifying a set
of extensions which should not be exercised.

This patch adds this support. To this aim, the tempest configuration
process will scan API endpoints for active extensions using the
verify_tempest_config.py tool, and then will remove those extensions
which have been explicitly disabled by the user.

If an explicit subset of extensions to enable is passed to devstack,
tempest will use this subset, rather than the list of active
extensions.

Implements blueprint branchless-tempest-extensions

Change-Id: I263bcf04668953f414a4ef18cb98c1c373e142ad
XenAPI: Add another plugin directory

Buildroot on 64-bit systems may use /usr/lib64 to store the XAPI plugins
Add this as an option to search for.

The list is getting of acceptable paths is getting longer but some work is going
on in XAPI to allow us to query for this path, which will mean we can get
rid of this list in future.

Change-Id: I79aafb6a86032c7ab04937c9e9bec08661ecdefa
Merge "Add tooz support from Oslo"
Merge "Fix variable typo of use_syslog in lib/tempest"
Merge "XenAPI: Add another plugin directory"
add shebang lines to all lib files

With gerrit 2.8, and the new change screen, this will trigger syntax
highlighting in gerrit. Thus making reviewing code a lot nicer.

Change-Id: Id238748417ffab53e02d59413dba66f61e724383
Merge "Tempest: configure exact set of extensions to test"
Merge "add shebang lines to all lib files"
Merge "Update devstack to work with new split neutron services repos"
Deprecate SCREEN_LOGDIR in favor of LOGDIR

This is the first step in the log file cleanup.  If SCREEN_LOGDIR
is still set, symlinks will be created in the old screen log directory
so things like the devstack-gate log collector continues to work.

bp:logging-and-service-names
Change-Id: I3ac796e322a18dbd0b8b2310a08310ca159d7613
Merge branch 'screen-logdir' into dt-test
Merge branch 'nonovnc' into dt-test
Merge branch 'identity-v3-default' into dt-test
Merge branch 'conf-tempest' into dt-test
Merge branch 'test-service-functions' into dt-test
Merge branch 'exercise-refresh' into dt-test