[pkg-ntp-maintainers] Bug#838104: ntpd fails to use dhcpcd provided servers on first run

[Daniel L. Srebnick]

Package: ntp
Version: 1:4.2.6.p5+dfsg-7+deb8u2

Also involved, dhcpcd5 6.7.1-1+rpi5, also occurs on Intel/AMD platform
so not RPi specific.

On first boot, ntp fails to notice that dhcp servers have been provided
by dhcpcd.  However, manually restarting ntp fixes the situation.
 Likewise, adding a delay of 15 seconds to the init script just before
starting ntp and then a reboot also cures the problem.

This can be reproduced by removing the isc dhcp client from the system
and enabling dhcpcd.service.

It seems that dhdpcd is possibly not quite done updating
/var/lib/ntp/ntp.conf.dhcp before ntp tries to use it.  Also, deleting
/etc/ntp.conf and then rebooting, ntp gets the servers just fine but
obviously no other options that would normally be picked up from
/etc/ntp.conf.

This under Debian Jessie (both Intel and RPi), kernel 4.1.19-v7+ on the
RPi.