You might end up with a situation where you have tons of pack files, e.g.
when using hg2git. In this situation, all kinds of operations may
end up with a "too many files open" error. Let's recover gracefully from
that.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Looks-right-to-me-by: Shawn O. Pearce <spearce@spearce.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>