[954] Fix $recursiveAnchor in schema to match spec

The spec allows values of false. This fixes the schema to match the spec.

Author: ssilverman

meta/core.json

@@ -33,7 +33,6 @@
         },
         "$recursiveAnchor": {
             "type": "boolean",
-            "const": true,
             "default": false
         },
         "$vocabulary": {