Enlarge VM cpu & memory configuration to avoid OOM

The default 2GB memory of VM may cause start platform failed, like below:

Dec 22 05:18:12 deis-1 systemd[1]: deis-builder.service: main process exited, code=exited, status=1/FAILURE
Dec 22 05:18:12 deis-1 sh[29516]: 2014/12/22 05:18:12 Error response from daemon: Cannot start container c0ac3fd6987742b235fd964ba6bd245cf7a51fa68f3940afcd21d5814989d83a: iptables failed: iptables --wait -t nat -A DOCKER -p tcp -d 0/0 --dport 2223 ! -i docker0 -j DNAT --to-destination 10.1.66.25:22:  (fork/exec /usr/sbin/iptables: cannot allocate memory)

core@deis-1 ~ $ free
             total       used       free     shared    buffers     cached
Mem:       2054232    1953844     100388      11064       1536     390876
-/+ buffers/cache:    1561432     492800
Swap:            0          0          0

So enlarge VM configuration to 2core, 4GB memory to avoid this error.

Signed-off-by: Chengwei Yang <yangchengwei@qiyi.com>