CLOUDSTACK-6075: Increase the ram size for router service offering

Increased the ram size of Internal load balancer vm service offering also
Backported from fix by Harikrishna Patnala <harikrishna.patnala@citrix.com>
https://reviews.apache.org/r/17941/

Signed-off-by: Rohit Yadav <rohit.yadav@shapeblue.com>