mod_image_for_recovery: switch to command_completed

This is the intended API for tools.

BUG=None
TEST=CQ passes

Change-Id: I02d695012bae01c5459dcca3edd690845d653606
Reviewed-on: https://chromium-review.googlesource.com/1769678
Tested-by: Mike Frysinger <vapier@chromium.org>
Commit-Ready: Mike Frysinger <vapier@chromium.org>
Legacy-Commit-Queue: Commit Bot <commit-bot@chromium.org>
Reviewed-by: Michael Mortensen <mmortensen@google.com>
diff --git a/mod_image_for_recovery.sh b/mod_image_for_recovery.sh
index 91766f1..40f030b 100755
--- a/mod_image_for_recovery.sh
+++ b/mod_image_for_recovery.sh
@@ -463,5 +463,5 @@
 install_recovery_kernel
 
 echo "Recovery image created at $RECOVERY_IMAGE"
-print_time_elapsed
+command_completed
 trap - EXIT