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

Signed-off-by: Rajani Karuturi <rajanikaruturi@gmail.com>
(cherry picked from commit c919ff83d81528b89017b5f5731b2e46350e3dfa)
CLOUDSTACK-7915: Remove hard-coded values for Load Balancer algorithms in UI

Signed-off-by: Rajani Karuturi <rajanikaruturi@gmail.com>
(cherry picked from commit ba6dfd84702eeef0362b94068add1328db84133a)
CLOUDSTACK-6465: vmware.reserve.mem is missing from cluster level settings

Signed-off-by: Rajani Karuturi <rajanikaruturi@gmail.com>
(cherry picked from commit eae733817b3670b0151410c027325f78013392ad)