Add dhcp-sequential-ip option to dnsmasq

For many simultaneously DHCPDISCOVER requests dnsmasq
can offer the same IP for two different MAC addresses.
This option prevents it by assigning IPs one by one
instead of using hashing algorithm.

Change-Id: Iff3c42d21e1f1c09cb9eab5f07dbb066508dcb56
Related-bug: 1378000
Related-bug: 1376680
Related-bug: 1379917
Blueprint: 100-nodes-support
Merge "Add dhcp-sequential-ip option to dnsmasq" into stable/5.1