don't frontload reconcileStaged in git-annex init

don't frontload reconcileStaged in git-annex init

init: Avoid scanning for annexed files, which can be lengthy in a
large repository. Instead that scan is done on demand. This lets git-annex
init be run and some query commands be used in a repository without
waiting.

Note that autoinit already behaved this way, so while this will mean some
commands like git-annex get/unlock/add will do the scan the first time run,
that is not really a significant behavior change.

And, it's really better to have a consistent behavior. The reason for
the inconsistency was a strange bug discussed in
b3c4579c7907147a496bdf2c73b42238d8b239d6. Avoiding reconcileStaged in
init will keep avoiding whatever that was.

Sponsored-by: Dartmouth College's DANDI project