lower-bounds check shouldn't downgrade opam-patched packages

[MisterDA]

I've noticed that the lower-bounds check will downgrade opam-patched packages, e.g., from ocaml-secondary-compiler 4.08.1-1 to 4.08.1. The patch has been applied in opam and is usually important. I suspect there's no value for this check to downgrade patches, it'd be nice if the solver could ignore them.

An example here.