chrome-sdk: exit with the exit code of the command being run.

An error code from a command being executed in the chrome SDK
environment should be passed through by the SDK.  So have the SDK exit
with the exit code of the command it is running.

BUG=None
TEST=Local

Change-Id: I31a100e06c775b22fc151fbb283b57e579819dd3
Reviewed-on: https://gerrit.chromium.org/gerrit/64799
Commit-Queue: Ryan Cui <rcui@chromium.org>
Reviewed-by: Ryan Cui <rcui@chromium.org>
Tested-by: Ryan Cui <rcui@chromium.org>
3 files changed