replaced depricated 'disable-msg' pylint pragma with 'disable'
locally disable pylint warnings triggered by interface definitions
unit tests: make _makeSUCTest() a local function

The TestGetUnversionedFiles._makeSUCTest() looks like a method but is
used as a local function. Change it to a proper function, to make it
less confusing.

This also fixes 'no-self-argument' pylint warning.
enable no-self-argument and no-method-argument pylint checks
Fix pyflakes warnings on post_build_request.py
Update post_build_request to match change_hook

Since 2e25ec71 change_hook no longer returns a JSON object with a
200 OK response code. Instead it returns a 202 Accepted code with
no data. This commit updates post_build_request.py to match this
behaviour.
Merge branch 'pylint-interfaces' of git://github.com/elmirjagudin/buildbot
Merge branch 'master' of git://github.com/gmarkall/buildbot