Allow use TNS compiled string for connection

This simple path will give ability to make connections like this:
```
"oracle": {
    "connector": "oracle",
    "tns" : "(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=xxx.xxx.xxx.xxx)(PORT=1521))(CONNECT_DATA=(SERVER=DEDICATED)(SID=MYDATABASE)))",
    "username": "user",
    "password": "pass"
  }
```
because with current code you can't create connection with SID like (SID=MYDATABASE)