389-ds-base security and bug fix update

[1.2.11.15-12]

• Resolves: Bug 910994 - PamConfig schema not updated during upgrade
• Resolves: Bug 910995 - Valgrind reports memleak in modify_update_last_modified_attr
• Resolves: Bug 910996 - DS returns error 20 when replacing values of a multi-valued attribute (only when replication is enabled)
• Resolves: Bug 911467 - DNA: use event queue for config update only at the start up
• Resolves: Bug 911468 - Error messages encountered when using POSIX winsync
• Resolves: Bug 911469 - dse.ldif is 0 length after server kill or machine kill
• Resolves: Bug 911474 - Invalid chaining config triggers a disk full error and shutdown
• Resolves: Bug 914305 - ns-slapd segfaults while trying to delete a tombstone entry
• Resolves: Bug 913228 - unauthenticated denial of service vulnerability in handling of LDAPv3 control data