Use single quotes in the jqueryCheck too.

Gruntfile.js

@@ -29,7 +29,7 @@ module.exports = function (grunt) {
               ' * Licensed under the Creative Commons Attribution 3.0 Unported License. For\n' +
               ' * details, see http://creativecommons.org/licenses/by/3.0/.\n' +
               ' */\n',
-    jqueryCheck: 'if (typeof jQuery === "undefined") { throw new Error("Bootstrap requires jQuery") }\n\n',
+    jqueryCheck: 'if (typeof jQuery === \'undefined\') { throw new Error(\'Bootstrap requires jQuery\') }\n\n',
 
     // Task configuration.
     clean: {

dist/js/bootstrap.js

@@ -4,7 +4,7 @@
  * Licensed under MIT (https://github.com/twbs/bootstrap/blob/master/LICENSE)
  */
 
-if (typeof jQuery === "undefined") { throw new Error("Bootstrap requires jQuery") }
+if (typeof jQuery === 'undefined') { throw new Error('Bootstrap requires jQuery') }
 
 /* ========================================================================
  * Bootstrap: transition.js v3.0.3