REPO-1058 / REPO-1242: REST API - list sites that person is member of - fix orderBy (id, title or role)

- fix orderBy validation as per existing capabilities
- TODO add tests (see REPO-1244)

git-svn-id: https://svn.alfresco.com/repos/alfresco-enterprise/alfresco/BRANCHES/DEV/5.2.N/root@130774 c4b6b30b-aa2e-2d43-bbcb-ca4b014f7261

source/java/org/alfresco/rest/api/Sites.java

@@ -77,4 +77,6 @@ public interface Sites
 	String PARAM_SITE_ID          = "id";
 	String PARAM_SITE_TITLE       = "title";
 	String PARAM_SITE_DESCRIPTION = "description";
+
+	String PARAM_SITE_ROLE = "role";
 }