upload_prebuilts: switch to lib.commandline for parsing

This gets us common flags for free.  We have to rename the old --debug
to --dry-run, but this is good as that's what this script is using that
flag already.

Also convert from the custom Usage helper to the standard parser.error.

Shouldn't be any real functional changes otherwise.

BUG=chromium:377211
TEST=`./buildbot/run_tests` passes

Change-Id: Iceff7e401994270d40cddbb3eeae356563a8b843
Reviewed-on: https://chromium-review.googlesource.com/201491
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
3 files changed