FS#397 - odhcpd: link prefix and route life time to UCI dhcp option 'leasetime'

[openwrt-bot]

EricLuehrsen:

Simply, odhcpd default router advertisement of a long time can cause difficulties when things go wrong. It would be beneficial to at least use DHCP 'leasetime' as the route lifetime. Additionally an option 'ra_lifetime' may be desirable also, and when its omitted 'leasetime' is used. In environments where "in network roaming" is common (large WiFi work site), shorter DHCP and RA times can help client devices automatically fix connectivity issues.

openwrt/odhcpd#93