#2299 Fix rtl typo

tasks/build.js

@@ -22,10 +22,10 @@ module.exports = function(callback) {
 
   // check for right-to-left (RTL) language
   if(config.rtl == 'both') {
-    gulp.start('built-rtl');
+    gulp.start('build-rtl');
   }
   if(config.rtl === true || config.rtl === 'Yes') {
-    gulp.start('built-rtl');
+    gulp.start('build-rtl');
     return;
   }