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".  The filename conveys the expectation that
the output won't change between two invocations of "git for-each-ref".

Test 'no bogus intermediate values during delete' also creates a file
named "unchanged".  However, in this test the reference is being
deleted, i.e. it _does change_.  The file itself isn't used for any
assertions in the test.

Don't create the unused and slightly misleading file "unchanged".

Signed-off-by: Andrei Rybak <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: rybak

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 &&