Local ivy repository defined in sbt launcher configuration doesn't respect useOrigin

Sbt sets useOrigin=true for the default ivy cache, however, that does not work for any ivy repository defined in sbt launcher configuration files. This is because ivy's useOrigin only applies to FileSystemResolver, but not URLResolver. 

A patch was proposed, but doesn't seem be taken: http://ant.1045680.n5.nabble.com/PATCH-Ivy-useOrigin-true-support-for-URLResolver-with-file-URLs-td5714566.html

This pull request will create FileSystemResolver if the ivy repository defined in the sbt launcher configuration file is a local file system one.

Also a unit test is added to this. The risk should be minimal.