[sudo-workers] Empty SUDOERS_SEARCH_FILTER bug

[Todd C. Miller]

It works fine for me with sudo 1.8.21, what version of sudo are you
testing?

$ grep search_filter /etc/ldap.conf 
# sudoers_search_filter sudoOrder=5
sudoers_search_filter

Results in queries like:

sudo: ldap search '(&(|(sudoUser=millert)(sudoUser=%staff)(sudoUser=%#20)(sudoUser=ALL))(&(|(!(sudoNotAfter=*))(sudoNotAfter>=20170831115629.0Z))(|(!(sudoNotBefore=*))(sudoNotBefore<=20170831115629.0Z))))'

sudo: ldap search '(&(|(sudoUser=+*)(sudoUser=%:*))(&(|(!(sudoNotAfter=*))(sudoNotAfter>=20170831115629.0Z))(|(!(sudoNotBefore=*))(sudoNotBefore<=20170831115629.0Z))))'

This was probably fixed by https://www.sudo.ws/repos/sudo/rev/54856973af41
Specifically, the hunk that changes how an empty CONF_STR is stored.

 - todd