Really fix accepting connections from "long" IPv6 address
Commit
ee01ac19 (v4.3.23) enlarged player member hostaddr from 32 to
46 characters, but missed natstr member nat_hostaddr. player_main()
copies hostaddr to nat_hostaddr. Can overrun the destination, but
fortunately just into nat_hostname.
Impact:
* Can makes praddr() print only a suffix of the address. Used by play
command, for player messages during login and logout, and for
logging.
* Can make player_main()'s test for "same address as last time" fail,
causing extra "Last connection" messages.
* Matching against econfig key privip is not affected.
* Journal event login is not affected.