Bad return code for causal read timeout

When causal read timeout happens
1) it returns ER_ERROR_ON_READ which is about reading from file
2) the above error code requires an errno to be supplied, which is not done, so it prints random int form the stack.

hence we get

mysql> select * from test.comm00 limit 3;
ERROR 1024 (HY000): Error reading file 'Causal wait failed.' (errno: -469761968)

and a confused client, which expects a meaningful errno from a filesystem operation.

Suggestion:
Use ER_LOCK_WAIT_TIMEOUT in this case cause semantically it is very close to the situation in question.