CLOUDSTACK-7917: Validating Load Balancer Rule when updating LB + unit test

Signed-off-by: Rajani Karuturi <rajanikaruturi@gmail.com>
CLOUDSTACK-7915: Remove hard-coded values for Load Balancer algorithms in UI

Signed-off-by: Rajani Karuturi <rajanikaruturi@gmail.com>
CLOUDSTACK-6465: vmware.reserve.mem is missing from cluster level settings

Signed-off-by: Rajani Karuturi <rajanikaruturi@gmail.com>