Have spec .rubocop.yml inherit from config in root directory

We want the root directory config to still apply inside this directory.

Change-Id: Ibe757086b1685811cc388c1488cd6f963993a10c
Fix all remaining cops in spec directory

There were just a couple of long lines that needed to be properly
wrapped.

Change-Id: Ideee364633e19a86650e105ca901d1a63669b9bd