ntp packages cause step time adjustment when leap second is inserted even though ntpd is working with '-x' (slew mode) option. this issue is documented in http://bugs.ntp.org/show_bug.cgi?id=2745 commit on upstream: https://github.com/ntp-project/ntp/commit/dd8119aed2accd68af2ec16d33d72f7152f1c978 backport patch: http://pkgs.fedoraproject.org/cgit/rpms/ntp.git/commit/ntp-4.2.6p5-xleap.patch?id=cad98fe3e43004f347cbca91569beaa8a52ff9a4
