hi,
I don't think there's a problem controlling your relay directly by you PLD, if the pin can provide enought current. Since every PLD, micro,... has fet controlled outputs, or open collector outputs. ( if you decided to do in this manner don't forget to put antiparalel (reversed) diode)).
Like many people say, if you are going to be more professional or simply you want to be more safety, use a transistor to drive solenoide. It doesn´t matter the type of transistor, i mean PNP NPN FET, MOSFET.... But be sure, you'll need more parts in you design.
Regards