t1302: don't create unused file

Test 'gitdir selection on unsupported repo' in t1302-repo-version.sh writes output of a "git config" invocation to file "actual". However, the test doesn't have any assertions for the file. The file was used by this test until commit b9605bc4f2 (config: only read .git/config from configured repos, 2016-09-12), before which "git config" was expected to print the bogus value of "core.repositoryformatversion" to standard output. Don't redirect output of "git config" to file "actual" in test 'gitdir selection on unsupported repo'. Signed-off-by: Andrei Rybak <rybak.a.v@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>