dev-util: Making psutil a run-time dependency fails devserver health check in lakitu.

BUG=b:144789878
TEST=Locally running the autest
RELEASE_NOTE=None

Change-Id: If8d4546c51d0365f534539285832ec3d8084654f
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/dev-util/+/1926571
Tested-by: Vaibhav Rustagi <vaibhavrustagi@google.com>
Reviewed-by: Amin Hassani <ahassani@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
diff --git a/health_checker.py b/health_checker.py
index 5d9ce20..1f816c7 100644
--- a/health_checker.py
+++ b/health_checker.py
@@ -15,7 +15,15 @@
 import time
 
 import cherrypy  # pylint: disable=import-error
-import psutil  # pylint: disable=import-error
+
+try:
+  import psutil
+except ImportError:
+  # Ignore psutil import failure. lakitu doesn't have psutil installed
+  # and for auto-update test, lakitu copies the devserver code and uses
+  # that to run the devserver. This results in failure of devserver
+  # and the auto-update test fails.
+  psutil = None
 
 import setup_chromite  # pylint: disable=unused-import
 from chromite.lib import cros_update_progress