Be more specific with the feedback from git

[squaremo]

When git has not quite been set up, because it needs a custom known_hosts or whatnot, the flux daemon constantly logs

caller=images.go:21 component=sync-loop error="getting unlocked automated services: git repo not ready"

and this is something of a misdirection. In part because it's not the underlying problem, just the visible one; but mainly because it doesn't say anything about why.

Logging the git mirroring attempts, and what is not happening, would be a good start. Suppressing the above line, or at least only reporting on state changes, would also be useful.