[geneus_main.py] Fix unexpected function responses caused by python gabage

[wkentaro]

caused by python gc strategy

[wkentaro]

before

src [1]:
> from geneus.geneus_main import package_depends_impl

src [2]:
> len(package_depends_impl('geneus'))
> 1

src [3]:
> len(package_depends_impl('roseus'))
> 55

src [4]:
> len(package_depends_impl('geneus'))
> 55

[wkentaro]

after

src [1]:
> from geneus.geneus_main import package_depends_impl
WARNING: Package "ompl" does not follow the version conventions. It should not contain leading zeros (unless the number is 0).

src [2]:
> len(package_depends_impl('geneus'))
> 1

src [3]:
> len(package_depends_impl('roseus'))
> 55

src [4]:
> len(package_depends_impl('geneus'))
> 1

[k-okada]

do we still need this?

[wkentaro]

I think so. This is confusing when we test the function test_depends_impl from IPython. (because the unexpected behavior only appears when test_depends_impl was called multiple times)