Autotest: Make archiving step configurable and disable it by default.

This change makes the archiving step configurable in
global_config.ini. The variable "enable_archiving" is disabled by
default.

The Autotest scheduler performs the archive step after parsing. This
step spawns an autoserv process, runs site_archive_results, and executes
rsync to copy .archive.log back to cautotest. We do not need this step
since all our test results are rsync'd back after running the tests.

BUG=chromium-os:33061
TEST=run tests with local autotest setup

Change-Id: I1f2aac8f92ebd2a4d10c4bd85be2d111063ad251
Reviewed-on: https://gerrit.chromium.org/gerrit/29056
Commit-Ready: Yu-Ju Hong <yjhong@chromium.org>
Reviewed-by: Yu-Ju Hong <yjhong@chromium.org>
Tested-by: Yu-Ju Hong <yjhong@chromium.org>
4 files changed