futility: updater: rename 'customlabel_tag' to 'custom_label_tag'

Per discussion, the 'custom_label_tag' is easier to read than
'customlabel_tag'. We should rename it before any real devices
have started using the different names.

BUG=b:169766857
TEST=make; build and run test
BRANCH=None

Change-Id: I3672e7b20bc85f79796470ba1a58c2896d26ff88
Signed-off-by: Hung-Te Lin <hungte@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/vboot_reference/+/3534491
Reviewed-by: Yu-Ping Wu <yupingso@chromium.org>
Commit-Queue: Yu-Ping Wu <yupingso@chromium.org>
5 files changed