Fix bug in service_stopper.

https://gerrit.chromium.org/gerrit/51254 introduced bug into the
service stopper logic where is_stopped was always true.

For example the most likely upstart status strings will create the
following values for is_stopped:

out_arr = ['tcsd start/running, process 507',
	   'tcsd stop/waiting',
           'status: Unknown job: tcsd_bogus'
          ]
for out in out_arr:
  is_stopped = 'start/running' not in out
  print is_stopped

>>> False
>>> True
>>> True

Previous change incorrectly assummed find would return 0 for a match
and 1 for not but it should have instead key'd off -1 for no match.

BUG=chrome-os-partner:19561
TEST=hardware_TPMCheck passes

Reviewed-on: https://gerrit.chromium.org/gerrit/56025
Reviewed-by: Scott Zawalski <scottz@chromium.org>
Commit-Queue: Todd Broch <tbroch@chromium.org>
Tested-by: Todd Broch <tbroch@chromium.org>
(cherry picked from commit 7d6386a862470be63bc607fcc0c0eb2b288923df)

Change-Id: Ib554b4d44602ca4456d21b782237b4cff386cff2
Reviewed-on: https://gerrit.chromium.org/gerrit/56086
Reviewed-by: Scott Zawalski <scottz@chromium.org>
Tested-by: Scott Zawalski <scottz@chromium.org>
diff --git a/client/cros/service_stopper.py b/client/cros/service_stopper.py
index 570ef47..0593bc9 100644
--- a/client/cros/service_stopper.py
+++ b/client/cros/service_stopper.py
@@ -43,7 +43,7 @@
         for service in self.services_to_stop:
             cmd = 'status %s' % service
             out = utils.system_output(cmd, ignore_status=True)
-            is_stopped = out.find('start/running') != 0
+            is_stopped = 'start/running' not in out
             if is_stopped:
                 continue
             try: