pull: pass upload_pack only when it was given
pull: pass upload_pack only when it was given

The upload_pack shell variable is initialized to an empty string, so
conditional expansion with ${upload_pack+"$upload_pack"} would not
work very well.  You need a colon there.

Signed-off-by: Junio C Hamano <a6723cc3f76163bf7adb636a73ac3b0ceb3e6b9b@pobox.com>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git