netd: Add dhcp option while starting dnsmasq.

Add dhcp-authoritative option which restores non-RFC
compliant but desirable behaviour of pre-2.14 versions and
avoids long timeouts while DHCP clients try to renew leases
which are unknown to dnsmasq.

Change-Id: I99d699b8d796b91cfb088510726cbf5998a2bac6
CRs-Fixed: 580493
netd: Validate input argument for Route commands

Check for valid command line argument that is
passed to RouteController module.

CRs-fixed: 569443
Change-Id: I06516d96fa1ab188e4ab3f81bf6c81be56b41aa5