t7701: fix ignored exit code inside loop

When checking a list of file mtimes, we use a loop and break
out early from the loop if any entry does not match.
However, the exit code of a loop exited via break is always
0, meaning that the test will fail to notice we had a
mismatch. Since the loop is inside a function, we can fix
this by doing an early "return 1".
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

t/t7701-repack-unpack-unreachable.sh

@@ -57,7 +57,7 @@ compare_mtimes ()
 {
 	read tref rest &&
 	while read t rest; do
-		test "$tref" = "$t" || break
+		test "$tref" = "$t" || return 1
 	done
 }