There's no easy way to get patch information using storm.schema

[Jamu Kakar]

I want to write a tool that can display the patch status of a
database. Specifically, I want to display unapplied patch versions
(and ideally, the module docstrings from the patches) and also unknown
patch versions. PatchApplier.get_unknown_patch_versions lets me do
the latter, but I can only do the former with
PatchApplier._get_unapplied_versions and there is no easy way to get
module docstrings from the patches themselves.