prevent administrators from being deleted - first remove them from admin group

src/socket.io/admin/user.js

@@ -98,15 +98,21 @@ User.deleteUsers = function(socket, uids, callback) {
 	}
 
 	async.each(uids, function(uid, next) {
-		user.delete(uid, function(err) {
+		user.isAdministrator(uid, function(err, isAdmin) {
-			if (err) {
+			if (err || isAdmin) {
-				return next(err);
+				return callback(err || new Error('[[error:cant-ban-other-admins]]'));
 			}
 
-			events.logAdminUserDelete(socket.uid, uid);
+			user.delete(uid, function(err) {
+				if (err) {
+					return next(err);
+				}
+
+				events.logAdminUserDelete(socket.uid, uid);
 
-			websockets.logoutUser(uid);
+				websockets.logoutUser(uid);
-			next();
+				next();
+			});
 		});
 	}, callback);
 };