RoleAssignInput hack for EZP-24700: Role assignment CRUD

RoleAssignInput.php.diff

--- a/eZ/Publish/Core/REST/Server/Input/Parser/RoleAssignInput.php
+++ b/eZ/Publish/Core/REST/Server/Input/Parser/RoleAssignInput.php
@@ -48,6 +48,8 @@ class RoleAssignInput extends BaseParser
      */
     public function parse(array $data, ParsingDispatcher $parsingDispatcher)
     {
+        $data = $data['Role']['document'];
+
         if (!array_key_exists('Role', $data)) {
             throw new Exceptions\Parser("Missing 'Role' element for RoleAssignInput.");
         }