fixup! TO-UNDO: diagnose where --quick would need to intercept
WIP: Introduce fsck --quick

This option avoids unpacking each and all objects, and just verifies
the connectivity.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
fixup! TO-UNDO: diagnose where --quick would need to intercept
TO-UNDO: probably unnecessary

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
fixup! TO-UNDO: probably unnecessary
fixup! TO-UNDO: diagnose where --quick would need to intercept
fixup! WIP: Introduce fsck --quick