change cleanup to keep compile metadata about resolution
change cleanup to keep compile metadata about resolution

agideon/heroku-buildpack-scala,yannickdeturck/heroku-buildpack-scala,Javilete/buildpack,heroku/heroku-buildpack-scala,Scalingo/scala-buildpack,hpcloud/heroku-buildpack-scala,shunjikonishi/heroku-buildpack-scala-compiled,phdezann/heroku-buildpack-scala,phdezann/heroku-buildpack-scala,KimStebel/heroku-buildpack-scala,Scalingo/scala-buildpack,Javilete/buildpack,KimStebel/heroku-buildpack-scala,agideon/heroku-buildpack-scala,shunjikonishi/heroku-buildpack-scala-compiled,hpcloud/heroku-buildpack-scala,yannickdeturck/heroku-buildpack-scala,heroku/heroku-buildpack-scala