Need to access upstream repo using downstream's GIT_COMMIT

[seanf]

I tried something like this as a "Specified Path in Repository"

repository/project/<some job name>/SHA1/$GIT_COMMIT/repository/

But instead of expanding the variable $GIT_COMMIT, it just appeared as is in the Jenkins.Repository variable.

It would be a useful enhancement to support variables here. Even better would be a friendly way of referencing a specific job's repo by the downstream's GIT_COMMIT.