[gms updater] Fixes and tests to prepare activation
- Fix broken download command on bots (uninitialized variable)
- Fix the issue where logs were not displayed when is_tty returned
False
- Check directory permissions
- ColorStreamHandler: allow forcing colorized output for non tty
- Add tests
BUG=
541727
Committed:
https://crrev.com/f04e2b29a270cd12200ffc71e35834158e32c22b
Cr-Commit-Position: refs/heads/master@{#358076}