Really compute transitive dependencies in opam_mk_repo (Close: #976).
Use 3.12 M.() to shorten the change.
Fix bugs in the way we visit all the dependencies graph for get_transitive_dependencies.
Fix typo in get_transitive_dependencies.
Merge pull request #977 from gildor478/master

Really compute transitive dependencies in opam_mk_repo (Close: #976).