io_u completion error propagation

Make sure we definitely signal an endio error.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/io_u.c b/io_u.c
index 6df4b5e..fa6302e 100644
--- a/io_u.c
+++ b/io_u.c
@@ -571,6 +571,7 @@
 	if (!icd.error)
 		return icd.bytes_done[0] + icd.bytes_done[1];
 
+	td_verror(td, icd.error, "io_u_sync_complete");
 	return -1;
 }
 
@@ -601,6 +602,7 @@
 	if (!icd.error)
 		return icd.bytes_done[0] + icd.bytes_done[1];
 
+	td_verror(td, icd.error, "io_u_queued_complete");
 	return -1;
 }