Merge branch 'jx/fetch-atomic-error-message-fix' into maint-2.43

"git fetch --atomic" issued an unnecessary empty error message,
which has been corrected.
cf. <ZX__e7VjyLXIl-uV@tanuki>

* jx/fetch-atomic-error-message-fix:
  fetch: no redundant error message for atomic fetch
  t5574: test porcelain output of atomic fetch

diff --cc t/t5574-fetch-output.sh
Simple merge