CLOUDSTACK-2461: createGSLBRule API is failing to pick the default algorithm "round
robin" for parameter "gslblbmethod"

fix defaults to round robin when parameter not specified
CLOUDSTACK-2460: fix the event descriptions for
create/delete/update/assign global load balancer rule apis
CLOUDSTACK-2529: GlobalLoadBalancerResponse should have the full FQDN
for the global load balanced service
CLOUDSTACK-2462: Failed to create GSLB rule with "proximity" algorithm

add RTT as load balancing method for GSLB vserver