Add common.py

We have a 'import common' in config.py but there is not such module.
The common module is suppose to set up sys.path for autotest_lib.*.

BUG=None
TEST=Run `python -c import config` in server/cros/faft/config directory.

Change-Id: Ie90feabf684e5a43b00b396cdb7af90fe9615036
Reviewed-on: https://chromium-review.googlesource.com/208925
Tested-by: Ricky Liang <jcliang@chromium.org>
Reviewed-by: Yusuf Mohsinally <mohsinally@chromium.org>
Reviewed-by: Vic Yang <victoryang@chromium.org>
Commit-Queue: Ricky Liang <jcliang@chromium.org>
1 file changed