Cleaned up doc string in cellular smoke

BUG=chromium:234294
TEST=run_all_tests.py

Change-Id: I78935463d8362fa8ef97f45035bd91ae97ae5ee0
Reviewed-on: https://chromium-review.googlesource.com/177556
Reviewed-by: Prathmesh Prabhu <pprabhu@chromium.org>
Commit-Queue: Byron Kubert <byronk@chromium.org>
Tested-by: Byron Kubert <byronk@chromium.org>
1 file changed