Change default route to DHCP interface without a route push?
I found the answer in: http://xmodulo.com/2012/03/how-to-set-default-route-in-linux.html
Removing any unnecessary default route leveraging post-up command in /etc/network/interfaces as follows. This will enable default route through eth0
$ sudo vi /etc/network/interfaces
allow-hotplug eth0
iface eth0 inet dhcp
allow-hotplug eth1
iface eth1 inet dhcp
post-up route del default dev $IFACE