fix date format on oracle

The expected format for DATE columns is `01-MAR-14`. See http://docs.oracle.com/cd/B28359_01/server.111/b28318/datatype.htm#CNCPT413

It also works with `01-Mar-2014` as this PR uses.

We found the problem when trying something like

```
$this->oracleCon->executeQuery(
    'SELECT * FROM table WHERE datefield > ?',
    array(new \DateTime()),
    array(Type::DATE)
);
```

which was raising an oracle error that the date could not be parsed.

The