git-lfs repos that encrypt the annexed content but not the git repo only
need --force passed to initremote, allow enableremote and autoenable of
such remotes without forcing again.
Needing --force again particularly made autoenable of such a repo not work.
And once such a repo has been set up, it seems a second --force when
enabling it elsewhere has little added value. It does tell the user about
the possibly insecure configuration, but if the git repo has already been
pushed to that remote in the clear, data has already been exposed. The goal
of that --force was not to prevent every situation where such an exposure
can happen -- anyone who sets up a public git repo and pushes to it will
expose things similarly and git-annex is not involved. Instead, the purpose
of the --force is to point out to the user that they're asking for a
configuration where encryption is inconsistently applied.