[autotest] add method add_logdir to site_sysinfo

add_logdir method can be called in control file for test to save files in a
specific folder, e.g.,
job.sysinfo.add_logdir('path to a folder')
before calling job.run_test

BUG=chromium:276919
TEST=None

Change-Id: I62d46d4d42efda1258be1ff5227bfed03d032afb
Reviewed-on: https://chromium-review.googlesource.com/182759
Tested-by: Dan Shi <[email protected]>
Reviewed-by: Alex Miller <[email protected]>
Commit-Queue: Dan Shi <[email protected]>
1 file changed