iscsi_aio_write16_cb, iscsi_aio_writev, iscsi_aio_read16_cb, and
iscsi_aio_readv have not not been in use since commit
063c3378 ("block/iscsi: introduce
bdrv_co_{readv, writev, flush_to_disk}").

These were the only trace events in block/iscsi.c so drop the the
trace.h include.

Cc: Peter Lieven <pl@kamp.de>
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>
Message-id: 1411394595-15300-4-git-send-email-stefanha@redhat.com