Fix so import on Py3

[cielavenir]

otherwise we will get strange error on Py3:

In [1]: from openravepy import interfaces

In [2]: import openravepy.interfaces
---------------------------------------------------------------------------
ImportError                               Traceback (most recent call last)
<ipython-input-2-9cacc8e081f9> in <module>
----> 1 import openravepy.interfaces

/usr/local/lib/python3.9/dist-packages/openravepy/_openravepy_/interfaces/__init__.py in <module>
      1 """Interface bindings
      2 """
----> 3 from .BaseManipulation import BaseManipulation
      4 from .Grasper import Grasper
      5 from .TaskManipulation import TaskManipulation

/usr/local/lib/python3.9/dist-packages/openravepy/_openravepy_/interfaces/BaseManipulation.py in <module>
     14 __license__ = 'Apache License, Version 2.0'
     15 # python 2.5 raises 'import *' not allowed with 'from .'
---> 16 from ..openravepy_int import RaveCreateModule, RaveCreateTrajectory, matrixSerialization, IkParameterization
     17 from .. import PlanningError
     18 

ImportError: generic_type: type "Environment" is already registered!

[cielavenir]

autotester pipelineid=272815

[cielavenir]

why it fails on Py2...

[cielavenir]

pipelineid=272825

[rdiankov]

thanks~