Build log_handler documentation

When log_handler.py was added to oslo.messaging changes weren't made to
publish the documentation. This patch ensures the docs for log_handler
are built.

Change-Id: Ibf60f648ad07875fb4c61427e601b6b268a95f53
Closes-Bug: 1286984
Updated from global requirements

Change-Id: I30e46e95cbfc3024b1a1ab0de8bd79bf9e80d322
Remove vim header

We don't need vim modelines in each source file, it can be set in
user's vimrc.

Change-Id: I615f1ffc7e097f1ddbd908a512f1cb988489e871
Closes-Bug: #1229324
Add kombu driver library to requirements.txt

The RabbitMQ driver is the default driver for oslo.messaging, so it
makes some sense to require this by default. This is consistent with
the way e.g. Nova has always required kombu.

Change-Id: Ibcab58e3f3edce794b571cfabc0a5bcf96c9b47e
Closes-Bug: #1288425
Merge "Add kombu driver library to requirements.txt"
Merge "Build log_handler documentation"
Merge "Remove vim header"