ocaml/opam — pull request #1109 by samoht (2014-01-19 17:00:10+00:00)
Title: Never downgrade packages on upgrade

This is related to #985

Seems to work well with my limited tests.

Remark 1: this changes the request which is sent to the external solver as well, which is maybe not what we want to do.

Remark 2: this should help giving the right conflict errors, as discussed on #1105