Make role name validation case insensitive

Role names are not case sensitive,
so need to convert the name to lowercase and make a judgement.

Change-Id: I389d264004d7cd3adce1784a3a9fcf89f994fcdf
Closes-Bug: #1821679

openstack_dashboard/dashboards/identity/static/dashboard/identity/roles/actions/create.action.service.js

@@ -61,7 +61,7 @@
         },
         $validators: {
           rolesExists: function (name) {
-            return (roles.indexOf(name) === -1);
+            return (roles.indexOf(name.toLowerCase()) === -1);
           }
         }
       }
@@ -118,7 +118,7 @@
     }
 
     function getName(item) {
-      return item.name;
+      return item.name.toLowerCase();
     }
 
   }