AS-288: Check deleted CLB when adding node
treq.json_content using side_effect instead of return_value

since mock_treq now uses side_effect
check PENDING_DELETE also
Refactored CLB or node deletion part - no tests

Moved it into separate function that raises CLBOrNodeDeleted exception
based on error. This is then used in add/remove to succeed/fail the
operation
CLBOrNodeDeleted has RequestError in it for inspection

- spit up LoadBalancerTests into add and remove tests
- Logging only unexpected non-PENDING_UPDATE errors
removed comment - thanks @cyli

According to @cyli: "I think this is still required. I think the fix
just makes it fail faster and with an obvious error, but it will still
fail."
using iter() and simpler message formatting - thanks @lvh
Better name and docstring - per @lvh
Merge branch 'master' into as-288-deleted-clb

Conflicts:
	otter/test/worker/test_launch_server_v1.py
Using mixin instead of Base test class - thanks @lvh

This is because trial will consider LoadBalancerTests as test which is
fine in this case since it doesn't have tests but I guess it is better
design to have it as mixin
using iter instead if list.pop() - thanks @lvh
sphinx class ref - thanks @lvh
Add json_content, get/put/post/head/delete, and return deferreds
Change request signature to match treq signature, by taking the method, url, and arbitrary keywords.  This means that the form of the dictionary needs to change.
Can't include the log in the request, since we can't always get the exact BoundLog instance
Make some changes to make treq injectable (rather than having to patch history), and attempt to use the StubTreq in a single test
Fix docstring
Just import logging_treq by its real name - thanks @manishtomar
Merge pull request #655 from rackerlabs/as-288-deleted-clb

AS-288: Check deleted CLB when adding node (review)
Merge pull request #669 from rackerlabs/stubtreq-additions

Add json_content, get/put/post/head/delete