removing unnecessary null checks

CityDoctorParent/CityDoctorModel/src/main/java/de/hft/stuttgart/citydoctor2/datastructure/Vertex.java

@@ -60,9 +60,6 @@ public class Vertex extends Vector3d {
 	}
 
 	void addAdjacentRing(LinearRing ring, Geometry geom) {
-		if (adjacentRings == null) {
-			adjacentRings = new ArrayList<>(2);
-		}
 		findAdjacentRingsForGeometry(geom).add(ring);
 	}