- Update ro 4.2.8p13
* CVE-2019-8936, bsc#1128525: Crafted null dereference attack in
authenticated mode 6 packet.
* Fix several bugs in the BANCOMM reclock driver.
* Fix ntp_loopfilter.c snprintf compilation warnings.
* Fix spurious initgroups() error message.
* Fix STA_NANO struct timex units.
* Fix GPS week rollover in libparse.
* Fix incorrect poll interval in packet.
* Add a missing check for ENABLE_CMAC.

- Drop use of $FIRST_ARG in ntp.spec
The use of $FIRST_ARG was probably required because of the
%service_* rpm macros were playing tricks on the shell positional
parameters. This is bad practice and error prones so let's assume
that no macros should do that anymore and hence it's safe to assume
that positional parameters remains unchanged after any rpm macro
call.