Convert knife ec2 server list to use aws sdk
Convert knife ec2 server list to use aws sdk

Signed-off-by: Tim Smith <764ef62106582a09ed09dfa0b6bff7c05fd7d1e4@chef.io>

chef/knife-ec2,chef/knife-ec2,MsysTechnologiesllc/knife-ec2,ClogenyTechnologies/knife-ec2,MsysTechnologiesllc/knife-ec2