futility: updater: increase verbosity on retries

To get more message for debugging, we want to increase the verbosity on
each retry.

BUG=None
TEST=build and run tests
BRANCH=None

Signed-off-by: Hung-Te Lin <hungte@chromium.org>
Change-Id: I85e0fc518113a18bb1aaa39db3f58329d94b5ecb
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/vboot_reference/+/3500326
Reviewed-by: Subrata Banik <subratabanik@chromium.org>