Update fixture to ignore script tag without src attribute

I was using jasmine-jquery to help test the jquery.cycle2.js plugin and it uses `<script>` tags to contain template data. jasmine-jquery was trying to use ajax to load the `src` attribute of the `<script>` tag, but in this case I didn't want that. I updated the code to only look for `<script>` tags with the `src` attribute. I added a unit test that fails without the fix and passes with the fix. Thank you for your helpful library.