t7406-submodule-update: add missing &&

322bb6e (2011 Aug 11) introduced a new subshell at the end of a test
case but omitted a '&&' to join the two; fix this.

Signed-off-by: Tay Ray Chuan <rctay89@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t7406-submodule-update.sh

@@ -58,7 +58,7 @@ test_expect_success 'setup a submodule tree' '
 	 git submodule add ../merging merging &&
 	 test_tick &&
 	 git commit -m "rebasing"
-	)
+	) &&
 	(cd super &&
 	 git submodule add ../none none &&
 	 test_tick &&