t4104: drop hand-rolled error reporting

t4104: drop hand-rolled error reporting

This use of "||" fools --chain-lint into thinking the
&&-chain is broken (and indeed, it is somewhat broken; a
failure of update-index in these tests would show the patch
file, even if we never got to the part of the test where we
fed the patch to git-apply).

The extra blocks were there to include more debugging
output, but it hardly seems worth it; the user should know
which command failed (because git-apply will produce error
messages) and can look in the trash directory themselves.

Signed-off-by: Jeff King <redacted>
Signed-off-by: Junio C Hamano <redacted>