Just read a thread on camping etiquette and dogs

I don't think the OP did anything wrong. If the RV Park doesn't have identified "dog restroom" areas, then you use an area that is off to a corner, etc. that is unlikely to be used for play, etc. and you clean up after the dog.

For those worried about the dog pee in the grass, etc., you might also want to worry about all the spitting that is done these days. It is amazing where and when people spit and there is a lot more to be concerned about that is in the spit than is in pee.