Issue LIBCLOUD-499: Add support for ssh_config and proxycommand

since 1.10 paramiko supports ssh_config parsing and proxycommand.

Proxycommand is essential if you have a ssh gateway between you and your computes. Some big infrastructures does.
Should this be `>= 1 (1, 10)`  (you said this feature was added in 1.10?

Also, a better variable name would probably be `paramiko_post_1_10` or something like that since we are checking the version is also bigger, not just equal.