Fix install.tmpl input default value (#611)

* Fix install.tmpl input default value

* Update db_user to gitea

* Add when INSTALL_LOCK = false

public/js/index.js

@@ -209,6 +209,12 @@ function initInstall() {
         return;
     }
 
+    if ($('#db_host').val()=="") {
+        $('#db_host').val("127.0.0.1:3306");
+        $('#db_user').val("gitea");
+        $('#db_name').val("gitea");
+    }
+
     // Database type change detection.
     $("#db_type").change(function () {
         var sqliteDefault = 'data/gitea.db';