shred: remove unwanted padding in verbose messages

[BenWiederhake]

This is tested for in the GNU shred-passes test, so we don't have a choice if we want to stay compatible.

Found while getting ready for #5711.

[BenWiederhake]

CI failure due to flaky test_tail::test_retry9. See also #7756: These tests are flaky by nature.

[github-actions]

GNU testsuite comparison:

GNU test failed: tests/misc/tee. tests/misc/tee is passing on 'main'. Maybe you have to rebase?
Skipping an intermittent issue tests/timeout/timeout (passes in this run but fails in the 'main' branch)

[BenWiederhake]

I don't understand why misc/tee failed in this CI run, but it doesn't seem plausible that a change in shred caused it. The test log only says:

FAIL: tests/misc/tee
====================

tee: file.ro: Permission denied (os error 13)
FAIL tests/misc/tee.sh (exit status: 1)

So that's not really helpful.

Passes on my machine with this branch 😕

PASS: tests/misc/tee.sh
============================================================================
Testsuite summary for GNU coreutils 9.7-modified
============================================================================
# TOTAL: 1
# PASS:  1
# SKIP:  0
# XFAIL: 0
# FAIL:  0
# XPASS: 0
# ERROR: 0
============================================================================

[jtracey]

tee failure is a false positive, see the above issue mention

[cakebaker]

Thanks!