[PATCH] clone-pack and clone-script: documentation and add a missing parameter.

[PATCH] clone-pack and clone-script: documentation and add a missing parameter.

While adding the documentation for these two commands, I noticed
that the name of the program on the other end (git-upload-pack)
is already almost configurable but git-clone-pack lacked command
line parameter parsing to actually use anything but default, so
I introduced --exec= like other remote commands while I was at it.

Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>