Check for VPN Objects when deleting interfaces

When we delete Router interfaces/gateway,
we need to check if any VPN services are
associated with that router.

Closes-Bug:1261598

Change-Id: I7df2b8b130b47ec070d0b0a36b1a62df40532760
mock.assert_called_once() is not a valid method

mock.assert_called_once() is a no-op that tests nothing. Instead
mock.assert_called_once_with() should be used (or use
assertEqual(1, mock_obj.call_count) if you don't want to check
parameters).

Borrowed HACKING rule from Davanum Srinivas's nova patch to
prevent it from appearing again.

Change-Id: Idac1d3c89c07e13c9a209663f4e557fcb7547821
Closes-Bug: #1365751
Closes-Bug: #1300265
Updated cache module and its dependencies

This is to avoid cache module dependency on timeutils that are now moved
to oslo.utils.

The following changes are included:

 * neutron/openstack/common/cache/_backends/memory.py
  6ff6b4b Switch oslo-incubator to use oslo.utils and remove old modules
  2bedce3 Fix MemoryBackend not purging item from _keys_expired on delete

 * neutron/openstack/common/cache/backends.py
  39625e1 Set pbr 'warnerrors' option for doc build

 * neutron/openstack/common/cache/cache.py
  9c683be fix small typo

 * neutron/openstack/common/lockutils.py
  5d40e14 Remove code that moved to oslo.i18n
  7209975 Always log the releasing, even under failure
  bbb266c Clarify logging in lockutils
  942e1aa Use file locks by default again
  ac995be Fix E126 pep8 errors
  15b8352 Remove oslo.log from lockutils

Change-Id: I02cb4b2bc4b7bcba948e67cffdb8bd0219c89a29
Modify docstring on send_delete_port_request in N1kv plugin

N1kv plugin: Modify docstring on _send_delete_port_request method

Change-Id: I64d34878ffd8f6db703e4c1d9849032fef9bae96
Closes-Bug: #1381277
Merge "Updated cache module and its dependencies"
Merge "mock.assert_called_once() is not a valid method"
Merge "Modify docstring on send_delete_port_request in N1kv plugin"
Merge "Check for VPN Objects when deleting interfaces"
Merge branch 'master' of https://github.com/openstack/quantum