[autotest] Tweak the logging message for failed triggers.

When we start a repair action, we log the failed triggers.
This changes the message around the logging to make more sense
in context.

Sample before:
Attempting this repair action: Wait for update, then reboot servo host.
Repair was triggered by these failures:
    pwr_button control is normal
    lid_open control is normal

Sample after:
Attempting this repair action: Wait for update, then reboot servo host.
Repairing because these triggers failed:
    pwr_button control is normal
    lid_open control is normal

BUG=None
TEST=unit tests

Change-Id: I551b982ae55d099b615b6a82637120bc61e3c272
Reviewed-on: https://chromium-review.googlesource.com/376258
Tested-by: Richard Barnette <jrbarnette@chromium.org>
Reviewed-by: Kevin Cheng <kevcheng@chromium.org>
Commit-Queue: Richard Barnette <jrbarnette@chromium.org>
diff --git a/client/common_lib/hosts/repair.py b/client/common_lib/hosts/repair.py
index 3a97c5b..67c0201 100644
--- a/client/common_lib/hosts/repair.py
+++ b/client/common_lib/hosts/repair.py
@@ -420,7 +420,7 @@
         except AutoservVerifyDependencyError as e:
             e.log_dependencies(
                     'Attempting this repair action',
-                    'Repair was triggered by these failures')
+                    'Repairing because these triggers failed')
             host.record('START', None, self._repair_tag)
             try:
                 self.repair(host)