gooftool: Fix race condition of cannot probe modem version

To probe modem version, we need to stop modemmanager.
Previously we wait for 2 seccodns after `stop modemmanager`.
Sometimes the wait time is not enough and the modem version couldn't be
probed. The CL waits 1 second * 10 iterations at most and stops waiting
immediately once modemmanager stops.

BUG=chrome-os-partner:32871
TEST=manual

Change-Id: Ifaa1014b3a99ccc4e9ba9865c5dcd547c4324c96
Reviewed-on: https://chromium-review.googlesource.com/226444
Reviewed-by: Bowgo Tsai <bowgotsai@chromium.org>
Tested-by: Bowgo Tsai <bowgotsai@chromium.org>
Commit-Queue: Bowgo Tsai <bowgotsai@chromium.org>
1 file changed