Require paramiko 1.10+

With the stock paramiko 1.9 package in Ubuntu 12.04, I was getting these errors:

```
$ ansible all -m ping
dev.aws.slice-data.com | FAILED => FAILED: global name 'hash_hostname' is not defined
www.aws.slice-data.com | FAILED => FAILED: global name 'hash_hostname' is not defined
...

$ head /etc/ansible/hosts
www.aws.slice-data.com ansible_ssh_user=ubuntu
dev.aws.slice-data.com
```

This stems from a bug in paramiko 1.9 where it's referencing a nonexistent global called hash_hostname.