pgsnapshot: Handle case where WayNodes might already be loaded

The WayMapper might already be loading node IDs when a Way
is retrieved, so this commit adds a check to see if the Way
already has a list of WayNodes before adding them to the Way
in WayDao.  Without this check, the WayNodes end up duplicated.

osmosis-pgsnapshot/src/main/java/org/openstreetmap/osmosis/pgsnapshot/v0_6/impl/WayDao.java

@@ -61,7 +61,10 @@ public WayDao(DatabaseContext dbCtx, ActionDao actionDao) {
 
 
 	private void loadFeatures(long entityId, Way entity) {
-		entity.getWayNodes().addAll(wayNodeDao.getAllRaw(entityId));
+        if ( entity.getWayNodes().size() == 0 )
+        {
+		  entity.getWayNodes().addAll(wayNodeDao.getAllRaw(entityId));
+        }
 	}