Have the mirror client upload the .cabal first
Have the mirror client upload the .cabal first

This brings the mirror client in line with the import client. Uploading the
.cabal file sets the metadata for the package, after which we can upload the
.tar.gz file.


tkvogt/hackage-server,snoyberg/hackage-server,grayjay/hackage-server,grayjay/hackage-server,erantapaa/hackage-server,ocharles/hackage-server,erantapaa/hackage-server,dzackgarza/hackage-server,tkvogt/hackage-server,agrafix/hackage-server,chrisdotcode/hackage-server,dzackgarza/hackage-server,chrisdotcode/hackage-server,haskell-infra/hackage-server,agrafix/hackage-server,edsko/hackage-server,edsko/hackage-server,ocharles/hackage-server,snoyberg/hackage-server