Fix loaderPlugin

It looks like at some point the module names were moved from `context` out to `context.scripts`.

It's not clear to me how to write a test for this. I tried copying `require-baseurl` into `require-loader`, but I can't get the new test to run with no modifications.
```
Running "jasmine:require-loader" (jasmine) task
Testing jasmine specs via phantom
>> Error: scripterror: Illegal path or script error: ['app'] at
>> _SpecRunner.html:21 
>> .grunt/grunt-contrib-jasmine/require.js:12 v
>> .grunt/grunt-contrib-jasmine/require.js:29 
```
output from: https://github.com/AsaAyers/grunt-template-jasmine-requirejs/commit/af02ba802f72cf995e29c82597fb79ca01b000e9