v3.1.0: Various bug fixes for EC2 class.
- Check for ssh key file separately in ec2. - Add specific commands for GCE credentials setup. - SSH user key in ec2utils config is user. - Accept availability zones as ec2 region.
- Check for ssh key file separately in ec2. - Add specific commands for GCE credentials setup. - SSH user key in ec2utils config is user. - Accept availability zones as ec2 region.