CLOUDSTACK-5408 [Automation] Failed to deploy vm in vmware environment with error "due to java.io.IOException: Cannot run program "mount": java.io.IOException: error=12, Cannot allocate memory"

Bump up RAM size of system offering for SSVM to 512MB. Fix if default service offering is already not present.

Signed-off-by: Sateesh Chodapuneedi <sateesh@apache.org>