Improperly munged output path for GClosure JavaScript lib in build source dir.

When a GClosure file respects the CLJS namespace and file naming conventions, and provides a namespace as follows

src/strange_loop/code.js

When this file is copied to the output directory it is copied to
out/strange-loop/code.js. This path has a hyphen instead of an underscore.

You can see this behavior in the cljs_deps.js file as well.

out/cljs_deps.js

This seems to be the result of the interaction these two functions