Use -x CLI option to set ssh_user when ssh bootstrap protocol is used during server create
Fixed unit test for server create
Added unit tests for -p, -i and -P CLI option to set ssh_port, identity_file and ssh_password respectively when ssh bootstrap protocol is used during server create
Merge pull request #162 from opscode/adamed-oc-10172

OC-10172: Knife ec2 ignores -x for ssh bootstrap, but honors it for winrm protocol