Handle case when make_vector is called with NumPy arrays.

When make_vector() is called with pure NumPy arrays, it would fail to do
missing optional attributes. Fixed that.

Change-Id: I3a408229a6c9133eb371ae1ee2670ac90e534dd3
Merge topic 'misc_py_fixes' into master

68285068 Handle case when make_vector is called with NumPy arrays.