dnsmasq: bump to 2.77test5

A number of small tweaks & improvements on the way to a final release.
Most notable:

Improve DHCPv4 address-in-use check.
Remove the recently introduced RFC-6842 (Client-ids in DHCP replies)
support as it turns out some clients are getting upset.

Signed-off-by: Kevin Darbyshire-Bryant <kevin@darbyshire-bryant.me.uk>