When a use sets umask in login.conf(5) to 027 or 077 a subsequently
fetched /var/db/ntpd.leap-seconds.list will inherit the permissions
allowed by the umask, resulting in a file that may not be readable
ntpd running under the ntp account. This patch adds a umask command
to preempt the umask in login.conf(5) prior to fetching a new copy
of the leap-seconds file.

PR:		261298
Reported by:	Martin Waschbusch <martin@waschbuesch.de>

(cherry picked from commit c6806434)