Removed defaultConfig_ reference in demo.

defaultConfig_ is not accessible in compiled mode, and thus the code
using it caused an error.
This simply sets the smallGapLimit placeholder to 0.5, instead of
looking it up from defaultConfig_.

Closes #929

Change-Id: I2e81669858bff2e555e638e282c0643f5ea70ac0

demo/main.js

@@ -317,8 +317,7 @@ shakaDemo.postBrowserCheckParams_ = function(params) {
   }
 
   var smallGapLimit = document.getElementById('smallGapLimit');
-  smallGapLimit.placeholder =
-      shakaDemo.player_.defaultConfig_().streaming.smallGapLimit;
+  smallGapLimit.placeholder = 0.5; // The default smallGapLimit.
   if ('smallGapLimit' in params) {
     smallGapLimit.value = params['smallGapLimit'];
     // Call onGapInput_ manually, because setting the value