applymbox: brown paper bag fix.

An earlier patch 87ab7992 broke applymbox by blindly copying piece
from git-am, causing a harmless but annoying series of error messages.

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

git-applymbox.sh

@@ -77,9 +77,9 @@ do
     *)
 	    git-mailinfo $keep_subject $utf8 \
 		.dotest/msg .dotest/patch <$i >.dotest/info || exit 1
-	    test -s $dotest/patch || {
+	    test -s .dotest/patch || {
 		echo "Patch is empty.  Was is split wrong?"
-		stop_here $this
+		exit 1
 	    }
 	    git-stripspace < .dotest/msg > .dotest/msg-clean
 	    ;;