Trac Ticket #346 - Slow ldapmodify operation time for large
quantities of multi-valued attribute values
https://fedorahosted.org/389/ticket/346
Fix Description: When comparing dn syntax attribute values (e.g.,
member in a group) with filter values, filter values are case-
lowered, but the attribute values in an entry are not any more.
This patch lowers the case before the comparison in the syntax
plugin.
(cherry picked from commit 091166e8c0642380d96cb495e30471b0bb4a5c94)