image_to_live.sh: move script here

This is the only repo left that uses this script, so move it here.
This is the same as the src/scripts/ file, so not doing style review.

BUG=None
TEST=precq passes

Change-Id: Ie5c19524503749a04655d1aa13eabec7b54af171
Reviewed-on: https://chromium-review.googlesource.com/1493351
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Tested-by: Mike Frysinger <vapier@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
diff --git a/lib/constants.py b/lib/constants.py
index bb87e33..25c4866 100644
--- a/lib/constants.py
+++ b/lib/constants.py
@@ -10,7 +10,9 @@
 
 _TEST_LIB_PATH = os.path.realpath(__file__)
 
-CROS_PLATFORM_ROOT = os.path.join(os.path.dirname(_TEST_LIB_PATH), '..', '..')
+CROSTESTUTILS_DIR = os.path.dirname(_TEST_LIB_PATH)
+
+CROS_PLATFORM_ROOT = os.path.join(CROSTESTUTILS_DIR, '..', '..')
 
 DEFAULT_CHROOT_DIR = 'chroot'