Bump version to 1.3.6.15-1
Ticket 49661 - CVE-2018-1089 - Crash from long search filter
Ticket 49631 - same csn generated twice
Ticket 49652 - DENY aci's are not handled properly
Ticket 49644 - crash in debug build
Ticket 49619 - adjustment of csn_generator can fail so next generated csn can be equal to the most recent one received