ASCII Null control character validation

Hello, hackers!

I found in src/backend/utils/mb/wchar.c: pg_verify_mbstr_len() that it
reports ASCII Null character (\000) as invalid. As for me, it should
pass validation. However, ASCII Null character breaks a line and the
end of the line is missed, try:

INSERT INTO mytable VALUES (E'a\001b\000c and rest of line MIA');

Find patch attached. Am I wrong?

-- 
Alexey Chernyshov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company