Fix for add_node operator: needs to have SKIP_SAVE set for the settings collection to prevent it from re-using settings from a previous call. This would otherwise lead to python exceptions when those properties don't exist for the other node type (point in case: node_tree only is defined for group nodes).

git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@56613 954f8c5b-7b00-dc11-b283-0030488c597c