dark_resume: Disable dark resume on link for test image.

Latest code looks for the presence of dark_resume_suspend_durations
file to decide whether to enable legacy dark resume. We do not want
it to be enabled on test image as it breaks several autotests.

BUG=chromium:820503
TEST=./build_image on link an make sure legacy dark resume is not
     enabled on link for test image.

Change-Id: I8b562778001f789f5ac6c89561c24e119ac75311
Reviewed-on: https://chromium-review.googlesource.com/957719
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Tested-by: Todd Broch <tbroch@chromium.org>
Reviewed-by: Ravi Chandra Sadineni <ravisadineni@chromium.org>
(cherry picked from commit 989cf3f25bf80243ac98addebf42b42d0b9b67f3)
Reviewed-on: https://chromium-review.googlesource.com/972241
Reviewed-by: Kalin Stoyanov <kalin@chromium.org>
Commit-Queue: Todd Broch <tbroch@chromium.org>
diff --git a/mod_for_test_scripts/200disableDarkResume b/mod_for_test_scripts/200disableDarkResume
index c78797e..443e98d 100755
--- a/mod_for_test_scripts/200disableDarkResume
+++ b/mod_for_test_scripts/200disableDarkResume
@@ -6,3 +6,9 @@
 
 mkdir -p "${ROOT_FS_DIR}/usr/share/power_manager"
 echo 1 > "${ROOT_FS_DIR}/usr/share/power_manager/disable_dark_resume"
+
+# This file is only present on link currently. Presence of this file will
+# automatically enable legacy_dark_resume.cc. Enabling legacy_dark_resume.cc
+# will hinder tests that use wakeup alarm for waking up for suspend.
+# So deleting the file.
+rm -f "${ROOT_FS_DIR}/usr/share/power_manager/board_specific/dark_resume_suspend_durations"