paycheck: perform payload integrity check by default

Currently, paycheck requires that --check, or one of its sub-options
(e.g.  --type), is specified explicitly on the command-line in order to
trigger full payload checking. This means that invoking paycheck without
*any* optional arguments will amount to loading the payload manifest and
quitting. This is not a useful behavior.

Instead, we want payload integrity check to be the default behavior when
nothing else is requested. This also edits the help text to clarify the
distinction between verifying/applying a payload, and what guarantees
are provided wrt the actual CrOS update engine.

BUG=None
TEST=Payload checking triggered when no other argument is given; passes
unit/integrity testing.

Change-Id: I8199813d4654f5598fcf152a3cdc62efbfc533da
Reviewed-on: https://gerrit.chromium.org/gerrit/48373
Tested-by: Gilad Arnold <garnold@chromium.org>
Reviewed-by: Darin Petkov <petkov@chromium.org>
Commit-Queue: Gilad Arnold <garnold@chromium.org>
1 file changed
tree: e2067593237107b4183be8ff823de7d3db743a88
  1. scripts/