escape special chars when creating group filter.
escape special chars when creating group filter.

The LDAP search filter used for group queries needs to be escaped so that group names with special characters will not break the search filter in queries.
ngoduykhanh/PowerDNS-Admin,ngoduykhanh/PowerDNS-Admin,ngoduykhanh/PowerDNS-Admin,ngoduykhanh/PowerDNS-Admin