Consolidate all the .rubocop.yml into a single file, finished out cleanups for
all the Ruby files.
Change-Id: I92d5983724d5d0185cd25bea6a0f46657a6c05d4
Addresses: blueprint rubocop-for-block-storage
The Testing section of the README.md was broken out into the new TESTING.md to
explain how the cookbook is being tested. Rubocop is testing the attributes/
files and the .rubocop.yml has documented excluded rules.
Change-Id: I0a5f4124a061617779425490d198c00d931c4cc1