Latest changes break multipack (at least with the nginx buildpack)

[a-warner]

One of the two latest pull requests to be merged (#20 and #18) seems to have introduced a regression (at least when this buildpack is used with the nginx buildpack). Here is the error output I'm seeing:

-----> Fetching custom git buildpack... done
-----> Multipack app detected
=====> Downloading Buildpack: https://github.com/ryandotsmith/nginx-buildpack
=====> Detected Framework: nginx-buildpack
cp: cannot stat `bin/nginx-cedar': No such file or directory

 !     Push rejected, failed to compile Multipack app

It seems like the nginx buildpack isn't in the directory that it expects to be in when its compile script is run, so maybe this is an issue for other buildpacks as well?

If I revert back to 935057 everything works again.

[a-warner]

(probably related to #20)

[ddollar]

Reverted in ae87c1b

[a-warner]

Thanks @ddollar !