Enlarge the RAM of the nodes in virtual deployment

Enlarge the RAM of the nodes in virtual deployment

Now the RAM of controller node in virtual deploymeny is only 4GB.

[root@host-10-20-11-6 ~]# free -h
              total        used        free      shared  buff/cache   available
Mem:           3.7G        3.2G        145M        1.7M        408M        191M
Swap:          4.0G        4.0G        2.3M

Since the RAM on the deploy server is at least 64GB (see installation
guide), we can enlarge every node's RAM to improve the performance.

Signed-off-by: Alex Yang <yangyang1@zte.com.cn>
Change-Id: Ie4e1297697e349a6b3edf0fa0c54eeeb94255ca8
Signed-off-by: Alex Yang <yangyang1@zte.com.cn>