t1402: check for refs ending with a dot

This has been illegal since cbdffe40 (check_ref_format(): tighten
refname rules, 2009-03-21), but we never tested it.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

t/t1402-check-ref-format.sh

@@ -48,6 +48,7 @@ invalid_ref './foo/bar'
 invalid_ref 'foo/./bar'
 invalid_ref 'foo/bar/.'
 invalid_ref '.refs/foo'
+invalid_ref 'refs/heads/foo.'
 invalid_ref 'heads/foo..bar'
 invalid_ref 'heads/foo?bar'
 valid_ref 'foo./bar'