Reduce verbosity of logging for ADB commands.
Reduce verbosity of logging for ADB commands.

By default, every single ADB command was being emitted to the swarming log. This
makes it very difficult to read the swarming log and figure out what's going on.
This CL reduces the verbosity to debug, which prevents the commands from making
it to the swarming log.

Bug: chromium:891898
Change-Id: I926dc9fda0b23fac132ce3ec975e12f37f4a8893
Reviewed-on: https://chromium-review.googlesource.com/c/1300153
Reviewed-by: John Budorick <17d38a2d68c6a07a3ab0ce4a2873c5acefbd3dbb@chromium.org>
Reviewed-by: Juan Antonio Navarro Pérez <1649bb5e6b9eafe026580e338065dc64ba6b80b2@chromium.org>
Commit-Queue: Erik Chen <b51d12b71fa2f8cb17021720ad5ee62fe09eb9e9@chromium.org>

catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult