[PATCH] remove "-r" option to xargs

git-prune-script still contained that non-portable option.
Signed-off-by: NJohannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

git-prune-script

@@ -20,6 +20,6 @@ sed -ne '/unreachable /{
     s|\(..\)|\1/|p
 }' | {
 	cd "$GIT_OBJECT_DIRECTORY" || exit
-	xargs -r $dryrun rm -f
+	xargs $dryrun rm -f
 }