Remove unused code in nova/api/ec2/__init__.py

"result = None" in nova/api/ec2/__init__.py#L546 is unused code, remove it

Change-Id: I1b09d8656686bafcc7f42bc77d01f3e14aa51ed9
Closes-Bug: #1265408
Sync config generator from oslo-incubator

Sync from oslo-incubator with the following patches about the config
generator:

7c18261 Temporary workaround for config generator
4b3e32b Sort the output of config/generator.py by group name
806272e Improve error reporting on import failures
6cd1c33 Clean up extra modules code
3d077a3 Print the deprecated group/name for each option
aec6d94 config.generator: allow extra modules importing
ddc4f0d Fix error when no custom config file matches *.conf.sample
d4bf84d Allow generate_sample MODULEPATH to be set in env

UpgradeImpact

DocImpact, the default values in keystone_authtoken config group are
changed.

Change-Id: If7181e14db2e43e42255bb6221d0543c13c4e5a6
Merge "Sync config generator from oslo-incubator"
Merge "Remove unused code in nova/api/ec2/__init__.py"
XenAPI: get_info was very expensive

Getting the whole VM record is expensive and slowed down Tempest tests
significantly.  Replaced with getting each required item.

When getting power state, only need that specific value, so reduce the
calls to get_info too.

Change-Id: I93bcef5b692a531aac41518dc29d5d4f46cded65
XenAPI: Tidy calls to get_all_ref_and_rec

get_all_records is more efficient than getting them individually in the
old get_all_ref_and_rec implementation.

Replaced some cases of get_all_records with a faster and more
specific API call.

Change-Id: I4725c3f1fdebdf1737941cb7db69b19afb22df9f
XenAPI: Speedup get_vhd_parent_uuid

In many cases the VDI record has already been retrieved.
Use it rather than expensively getting a new VDI record from XAPI.

Change-Id: I469e2a415c1f1924010f47d3927ca18c45a7b8f8
XenAPI: Use get_VALUE in preference to get_record()['VALUE']

Replaces calls to get_record where only a single item is retrieved
from the record with the specific get_VALUE call.

Change-Id: I52e20c4f4c9d6a6ad019694916ee057cc96b18a6
XenAPI: Monitor the GC when coalescing

Add a new host plugin to monitor whether the garbage collector is running.
This is then used by the wait_for_vhd_coalesce function to know whether
waiting any more is likely to produce the expected results.

Increased the number of times we loop waiting for coalesce as the loop
now has knowledge that something is still happening.

Change-Id: Idcc0738945bd1aee8cdb52c9cfabd798f85c31db
Closes-bug: 1258169

Conflicts:

	etc/nova/nova.conf.sample
	nova/virt/xenapi/vm_utils.py
XenAPI: Use direct IO for writing config drive

If you don't use direct IO when writing to the device, the unplug
immediately following this may not succeed as the device may still
be in use.

Also add a sync to ensure the device is not being used at the point
of unplug.

Closes-bug: 1259163

Change-Id: I68f09835648b36772a7839af9718123a4c60734f
XenAPI: Allow use of clone_vdi on all SR types

All XenServer SR types support VDI.clone - even if they perform
an internal VDI.copy.  Always use the clone function if COW is
enabled.

Change-Id: I85c580fba43d3bb52149626419d0f0c03ed69145