Persist automate state data between retries

https://bugzilla.redhat.com/show_bug.cgi?id=1044175

During the execution of an automate method the following 3 methods
can be called to set/get/check for existence of state data.

$evm.set_state_var     This takes a name and value as the 2 arguments
$evm.get_state_var     This takes a name and returns the corresponding value object
$evm.state_var_exist?  This takes a name and checks if the variable exists

The name in all 3 functions above can be a string or a symbol.
If the name is missing nil is returned.
@Fryguy forget it. the code was rebased out

---
for historical ref
I wasn't sure if there was a funky reason for assigning the variable back into the hash if we were just deleting it out. It was something like this:

```
args['ae_state_data'] = YAML.load(args['ae_state_data']) if args['ae_state_data']
ae_state = args.delete('ae_state_data')
```