Fix deprecation warning in test_multiprocessing

tests/functional/v1/test_multiprocessing uses psutil to get a list of
processes. The Processor class now uses children() instead of
get_children(); update the test with the current call to eliminate
the deprecation warning.

Change-Id: I83a6bb72b5282d3ab2a3b8e338ee3dc8668d2d53
Do not allow HEAD images/detail

Currently, a HEAD images/detail request goes through the images/{id}
route which leads to a 500 response status.
This HEAD method should be handled separetely in order to return a
405 Method Not Allowed response and suggest GET as an allowed method.

Change-Id: Ic83e819189bcff7c4735af476217a9ed1e4f41b8
Closes-Bug: #1297358
Merge "Fix deprecation warning in test_multiprocessing"
Merge "Do not allow HEAD images/detail"
Adds TaskStub class

Partial Task patch, Id I4fbadc9a97e3147128c7c733384c7bb50918806f
removed the result and message vars of the Tasks class. However,
the succeed and fail methods were using those to update them
respectively. This patch introduces a new TaskStub class which
enables the PartialTask functionality without looking result
and message attrs of the Task class.

Fixes bug 1284975

Change-Id: I0b406e4662cfd3cb496b71be77ad10a90c178baa
Merge "Adds TaskStub class"