The repo is Python 3 now, so update hacking to version 2.0 which
supports Python 3.
fix issues found by flake8.
Change-Id: I2f14cb6f67a0c9b4c0dcbf8d93c26eb99b9b9d33
This commit adds 'files' table. This files table has coverage_id
column as a foreign key for the coverages table. And this commit also
adds a release note for it.
Change-Id: I8998a79a1ba79bbdab1cd79810cc85bcbccbe7d8