Fixing a bad logic mistake where I the incorrect disk node type is queried...

Fixing a bad logic mistake where I the incorrect disk node type is queried against the wrong variable

utils/exporters/blender/addons/io_three/exporter/io.py

@@ -14,7 +14,7 @@ def copy_registered_textures(dest, registration):
 
 def copy(src, dst):
     logger.debug('io.copy(%s, %s)' % (src, dst))
-    if os.path.isfile(src):
+    if os.path.isdir(dst):
         file_name = os.path.basename(src)
         dst = os.path.join(dst, file_name)