gp_Vec can't be divided by float

On python2/pythonocc-0.16.4

```
>>> from OCC.gp import gp_Vec
>>> gp_Vec(1,2,3)/2
<OCC.gp.gp_Vec; proxy of <Swig Object of type 'gp_Vec *' at 0x02B3A728> >
```

On python3:

```
>>> from OCC.gp import gp_Vec
>>> gp_Vec(1,2,3)/2
>>>Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: unsupported operand type(s) for /: 'gp_Vec' and 'int'
```

why ?
