CLI Error while try to create the admin user with fuelphp 1.6

Hi,

i tested the latest warden version with fuelphp 1.6 and i got an error while try to create the admin user over the CLI .

I tested it with an db prefix.

Error message looks like:

```sql
:( Failed to create admin user because: Table 'fuel_league.lm_lm_users' doesn't exist [ (SELECT email FROM `lm_lm_users`
   WHERE email = 'admin@local.tld')
UNION
  (SELECT email FROM `lm_lm_users`
      WHERE username = 'admin')
LIMIT 1; ]
```

With this pull request, it should be fixed.

Tested with and without table prefix on my local osx environment (with MAMP).


Greets,
Marcus