Update usage of PropertyMap::load

Now that PropertyMap returns an owned object, update the usage in
validatekeymaps.

Bug: 163171599
Test: presubmit
Change-Id: I75b9abe3fa1d418951a8c23a624771046a89b3f8
diff --git a/PREUPLOAD.cfg b/PREUPLOAD.cfg
index fc5efc6..7a8d1a1 100644
--- a/PREUPLOAD.cfg
+++ b/PREUPLOAD.cfg
@@ -11,6 +11,7 @@
                libs/input/
                services/core/jni/
                services/incremental/
+               tools/
 
 [Hook Scripts]
 checkstyle_hook = ${REPO_ROOT}/prebuilts/checkstyle/checkstyle.py --sha ${PREUPLOAD_COMMIT}