fio: print io_u errors on one line

fio: print io_u errors on one line

Print io_u errors on one line and with one log_err command
to keep them from being interrupted by other prints

Old:
fio: io_u error on file /dev/sdt: Input/output error5.1MB/0KB/0KB /s]
[227K/0/0 iops] [eta 02d:10h:53m:36s]
     read offset=145442430976, buflen=4096
fio: io_u error on file /dev/sdt: Input/output error
     read offset=397760724992, buflen=4096

New:
fio: io_u error on file /dev/sdr: Input/output error: write offset=1532626153472, buflen=4096
fio: io_u error on file /dev/sdt: Input/output error: write offset=102684229632, buflen=4096

Signed-off-by: Robert Elliott <elliott@hp.com>
Signed-off-by: Jens Axboe <axboe@fb.com>