ls-remote and clone: accept --upload-pack=<path> as well.

This makes them consistent with other commands that take the
path to the upload-pack program.  We also pass --upload-pack
instead of --exec to the underlying fetch-pack, although it is
not strictly necessary.

[jc: original motivation from Uwe]

Signed-off-by: Junio C Hamano <junkio@cox.net>

git-clone.sh

@@ -163,7 +163,9 @@ while
 	1,-u|1,--upload-pack) usage ;;
 	*,-u|*,--upload-pack)
 		shift
-		upload_pack="--exec=$1" ;;
+		upload_pack="--upload-pack=$1" ;;
+	*,--upload-pack=*)
+		upload_pack=--upload-pack=$(expr "$1" : '-[^=]*=\(.*\)') ;;
 	1,--depth) usage;;
 	*,--depth)
 		shift