extensible filters and ACLs (ITS#3341)

[ando@sys-net.it]

Full_Name: Pierangelo Masarati
Version: HEAD
OS: Linux (irrelevant)
URL: ftp://ftp.openldap.org/incoming/
Submission from: (NULL) (81.72.89.40)


extensible filters cannot be used in ACLs because matchingRuleUse stuff has not
been computed yet at bi_config() time.

Possible fixes:
- defer filter evaluation when used in ACLs (may require extensive editing of
get_filter() stuff);
- introduce a new statement that forces matchingRuleUse computation (requires no
more schema stuff be read afterwards, or schema stuff read afterwards triggers
matchingRuleUse update).