t1404: don't create unused file

Some tests in file t1404-update-ref-errors.sh create file "unchanged" as
the expected side for a test_cmp assertion at the end of the test for
output of "git for-each-ref".  Test 'no bogus intermediate values during
delete' also creates a file named "unchanged" using "git for-each-ref".
However, the file isn't used for any assertions in the test.  Instead,
"git rev-parse" is used to compare the reference with variable $D.

Don't create unused file "unchanged" in test 'no bogus intermediate
values during delete' of t1404-update-ref-errors.sh.

Signed-off-by: Andrei Rybak <rybak.a.v@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t1404-update-ref-errors.sh

@@ -551,7 +551,6 @@ test_expect_success REFFILES 'no bogus intermediate values during delete' '
 	git update-ref $prefix/foo $C &&
 	git pack-refs --all &&
 	git update-ref $prefix/foo $D &&
-	git for-each-ref $prefix >unchanged &&
 	# Now try to update the reference, but hold the `packed-refs` lock
 	# for a while to see what happens while the process is blocked:
 	: >.git/packed-refs.lock &&