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/tools/validatekeymaps/Main.cpp b/tools/validatekeymaps/Main.cpp
index 7c150f9..0af6266 100644
--- a/tools/validatekeymaps/Main.cpp
+++ b/tools/validatekeymaps/Main.cpp
@@ -115,13 +115,13 @@
     }
 
     case FILETYPE_INPUTDEVICECONFIGURATION: {
-        PropertyMap* map;
-        status_t status = PropertyMap::load(String8(filename), &map);
-        if (status) {
-            error("Error %d parsing input device configuration file.\n\n", status);
+        android::base::Result<std::unique_ptr<PropertyMap>> propertyMap =
+                PropertyMap::load(String8(filename));
+        if (!propertyMap.ok()) {
+            error("Error %d parsing input device configuration file.\n\n",
+                  propertyMap.error().code());
             return false;
         }
-        delete map;
         break;
     }