properly preserve time elements original title on mouseover

don't replace it with the replacement

Author: jewel-andraia

lib/modules/localDate.js

@@ -17,7 +17,9 @@ modules['localDate'] = {
 		if ((this.isEnabled()) && (this.isMatchURL())) {
 			$('.sitetable')
 				.on('mouseenter', 'time', function() {
-					this.setAttribute('data-original-title', this.getAttribute('title'));
+					if (!this.getAttribute('data-original-title')) {
+						this.setAttribute('data-original-title', this.getAttribute('title'));
+					}
 					this.setAttribute('title', new Date(this.getAttribute('datetime')));
 				})
 				.on('mouseleave', 'time', function() {