[autotest] Fix metrics initialization for lab inventory.

The setup for metrics generation in lab inventory run was using
`short_lived=True,`.  ITOT that we prefer for that parameter to be
false.

BUG=chromium:775199
TEST=None

Change-Id: Ie4c0ffde6a506ffd183991f009e99108894d4b7c
Reviewed-on: https://chromium-review.googlesource.com/935834
Commit-Ready: Richard Barnette <jrbarnette@chromium.org>
Tested-by: Richard Barnette <jrbarnette@chromium.org>
Reviewed-by: Paul Hobbs <phobbs@google.com>
diff --git a/site_utils/lab_inventory.py b/site_utils/lab_inventory.py
index 2b5e33e..b746824 100755
--- a/site_utils/lab_inventory.py
+++ b/site_utils/lab_inventory.py
@@ -1313,8 +1313,7 @@
         if arguments.debug_metrics or not arguments.debug:
             metrics_file = None if not arguments.debug_metrics else '/dev/null'
             with site_utils.SetupTsMonGlobalState(
-                    'repair_loops', short_lived=True,
-                    debug_file=metrics_file,
+                    'repair_loops', debug_file=metrics_file,
                     auto_flush=False):
                 _perform_inventory_reports(arguments)
             metrics.Flush()