[PATCH 2/2] firewall implementation for eucalyptus driver

[sang-min . park]

This patch implements the firewall support in Eucalyptus driver. It's tested 
against eucalyptus-2.0.3.
Note the implementation supports the older definition of EC2 security group 
(http://docs.amazonwebservices.com/AWSEC2/2009-07-15/APIReference/index.html?ApiReference-query-AuthorizeSecurityGroupIngress.html
).