return the prune-packed progress display to the inner loop

return the prune-packed progress display to the inner loop

This reverts commit 0e549137966feb016927a827fb6e359aec8264a3 so to return
to the same state as commit b5d72f0a4cd3cce945ca0d37e4fa0ebbfcdcdb52.

On Wed, 31 Oct 2007, Shawn O. Pearce wrote:
> During my testing with a 40,000 loose object case (yea, I fully
> unpacked a git.git clone I had laying around) my system stalled
> hard in the first object directory.  A *lot* longer than 1 second.
> So I got no progress meter for a long time, and then a progress
> meter appeared on the second directory.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>