chrome_features: Swap default mode for Usbguard feature flag.

This feature flag is being used as a kill switch and default enabled
is needed for this functionality.

BUG=chromium:870769

Signed-off-by: Allen Webb <[email protected]>
Change-Id: Ie48ad82a261ce996a908852ac82a6a886807b857
Reviewed-on: https://chromium-review.googlesource.com/1176475
Reviewed-by: Steven Bennetts <[email protected]>
Cr-Commit-Position: refs/heads/master@{#583480}
1 file changed