I tried to upload a simple app to a local cf build, and it failed
because the go-buildpack download failed.
It turns out that the buildpack
had lost its pkzip header (but the end of the file looked like it was
part of a zip file).
When I moved it out of the way ('mv 75 hide-75') I got a stranger
error message, which unfortunately scrolled off my window before
I thought to report it.
What's the best way to push a faulty buildpack out of the cache?