Fix some defects in tensor module.

Now `test_args` pass.

Manual links to Travis:
2ed88738b6b4c98ddd129a8e19e2909098b3c374 https://travis-ci.org/sympy/sympy/builds/11082077
704b6580fa37acdbf58c9b12d3c470d81db34bc4 https://travis-ci.org/sympy/sympy/builds/11082192