directory_watcher: Demote logger.info to .debug

[EricCousineau-TRI]

• Motivation for features / changes: See Should demote log-level for directory_water - No path found ... (for library usage)? #5577. This is one alternative, to just demote to .debug for this component.

• Technical description of changes: In directory_watcher, demote usages of logger.info to logger.debug

• Screenshots of UI changes: N/A

• Detailed steps to verify changes work correctly (as executed by you): See workaround in [Feature]: Try to scrub annoying "No path found after" messages from tensorboard? wandb/wandb#3274

• Alternate designs / implementations considered: See Should demote log-level for directory_water - No path found ... (for library usage)? #5577 and [Feature]: Try to scrub annoying "No path found after" messages from tensorboard? wandb/wandb#3274

[bileschi]

Inclined to approve. Open for comments from others whether this will impede any common debugging flow.

[bileschi]

There is a little pushback within Google - the log line is useful for diagnosing troublesome TensorBoards sometimes, and we furthermore don't want to adopt an implicit mandate to maintain non-spammy info logs. Can we wait a week to see if the logs can be set to >=WARNING on the wandb side? If that avenue doesn't work we can proceed here with this limited change.

[EricCousineau-TRI]

Sounds great - thanks!