ec2 module - registers to ansible_facts key

Hi,

I discovered a bug into the previous version (I closed the request). It had to do with the fact that the module was not registering the ec2 facts to ansible_facts key.

Tested into a playbook as well 

```
---
- hosts: ec2_host
  gather_facts: yes
  tasks:
    - name: ec2 facts
      action:  ec2_facts
    - name: command
      action: command echo "ec2 facts tests"
      when_string: $ansible_ec2_profile == "default-paravirtual"
```

Sorry for inconvenience.