If I understand your post correctly you have a cable going to the light which has a live, neutral and earth, your new light fitting has no place for the earth.
So if the light is suitable to use in the bathroom, and you come to connect it up, power off, make sure the Earth wire has a bit of sleaving on it and then put a small bit of terminal block over the end of the wire ensuring that there in no copper showing and then just tuck it neatly at the side of the other connections.
Again please ensure power is off before you do any work. If there is more than one cable make sure you mark where all the wires connect into and take a photo.
If in doubt at all please ask for advice and don't just guess.