Mock out checking for a psql binary in a blackbox test

This test is intended to exercise moving files around to S3 and back
and already goes through pains to nix integration with Postgres, so
finish the job and remove the dependency that 'psql' has to be
installed and able to log in.
fsync newly restored files after a tar extract
add htmlcov to .gitignore
don't spin in a tight loop every, insert a 100ms sleep
add environment variable CRIPPLE_RETRIES=1 that skips wal-e retries