zbd: set thread errors in zbd_adjust_block()

zbd: set thread errors in zbd_adjust_block()

Several error conditions that are encountered during zone processing
in zbd_adjust_block() function cause it to return io_u_eof value.
This stops the i/o to the given file, but there is no error raised or
reported if this code is returned. For a few particular conditions,
just stopping the i/o is reasonable, but others are serious errors
that should be reported.

Add td_verror() calls to raise thread errors for a few abnormal
conditions during adjusting the i/o. The only test that needs to be
modified because of this changes is test #2.

Signed-off-by: Dmitry Fomichev <dmitry.fomichev@wdc.com>
Reviewed-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>