Refactor ec2 server delete options  - Added dry_run option.  - Updated the delete method to use AWS client.
Refactor ec2 server delete options
 - Added dry_run option.
 - Updated the delete method to use AWS client.

Signed-off-by: Vivek Singh <ffdfd29e24c206a3c24e1247563eb4c218c7ffa5@msystechnologies.com>

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