Fix regression with templates build introduced by fixing a bug in grunt-amd-build.

The `pluginBuilder` API was working before in this case, but only because of a bug in `grunt-amd-build`.

Using `pluginBuilder` will inline the following code in the layer:
```
define("delite/handlebars!path/to/template.html", "template string");
```
The problem is, when requirejs see this it will not use the load method of `delite/handlebars` but directly return `template string`.

After this PR the build output:
```
define("requirejs-text/text!path/to/template.html", "template string");
```
This way the template will still be compiled even if the code is built.