rpki-client does not do privsep and also no chroot to /var/empty. Change

the user to 'rpki-client user' and the homedir to /nonexistent since it is
not required for operation of rpki-client.
OK deraadt@

src/etc/master.passwd

@@ -23,7 +23,7 @@ _pkguntar:*:58:58::0:0:pkg untar user:/nonexistent:/sbin/nologin
 _spamd:*:62:62::0:0:Spam Daemon:/var/empty:/sbin/nologin
 www:*:67:67::0:0:HTTP Server:/var/www:/sbin/nologin
 _isakmpd:*:68:68::0:0:isakmpd privsep:/var/empty:/sbin/nologin
-_rpki-client:*:70:70::0:0:rpki-client privsep:/var/empty:/sbin/nologin
+_rpki-client:*:70:70::0:0:rpki-client user:/nonexistent:/sbin/nologin
 _syslogd:*:73:73::0:0:Syslog Daemon:/var/empty:/sbin/nologin
 _pflogd:*:74:74::0:0:pflogd privsep:/var/empty:/sbin/nologin
 _bgpd:*:75:75::0:0:BGP Daemon:/var/empty:/sbin/nologin