propagate --quiet to send-pack/receive-pack

propagate --quiet to send-pack/receive-pack

Currently, git push --quiet produces some non-error output, e.g.:

 $ git push --quiet
 Unpacking objects: 100% (3/3), done.

Add the --quiet option to send-pack/receive-pack and pass it to
unpack-objects in the receive-pack codepath and to receive-pack in
the push codepath.

This fixes a bug reported for the fedora git package:

 https://bugzilla.redhat.com/show_bug.cgi?id=725593

Reported-by: Jesse Keating <redacted>
Cc: Todd Zullinger <redacted>
Signed-off-by: Clemens Buchacher <redacted>
Signed-off-by: Junio C Hamano <redacted>