autotest: Fix ProcessWatcher behavior for arg-less processes

When no args are specified, ProcessWatcher tried to kill a process
like "command_name " rather than "command_name".  This caused the
pgrep/pkill pattern to not match, and the proces to live on.

BUG=brillo:641
TEST=Fake GCD servers are properly killed after this change.

Change-Id: Ibcda63dfb220d1e8c70347adc37577f7da112a59
Reviewed-on: https://chromium-review.googlesource.com/261774
Tested-by: Christopher Wiley <[email protected]>
Reviewed-by: David Zeuthen <[email protected]>
Commit-Queue: Christopher Wiley <[email protected]>
1 file changed