Fixed bad path when file is processed multiple times

Fixed bug that caused the path of the generated javascript file to
be appended multiple times with '.js', once for each time the
file was processed.  This resulted in the file's path going from
*.js to *.js.js to *.js.js.js, etc.

A file can be processed multiple times when you are using karma
in your development environment to proxy the resulting '.js' files
and you edit the underlying '*.html'.  Currently, you have to restart
karma everytime you edit an '*.html' file.