py3: make all tests in src/sage/tensor passed

[man74cio]

The parallelisation of the function a.__mul__(a) in src/sage/tensor/modules/comp.py was only one test failing with python3 in src/sage/tensor.
Previously, with python2.7, to create the partial result we used
a list comprehension but now it fails.
We have to replace it with a for loop.

CC: @egourgoulhon @fchapoton @tscrim

Component: geometry

Keywords: @parallel, pickle

Author: Marco Mancini

Branch/Commit: 2a481f1

Reviewer: Eric Gourgoulhon

Issue created by migration from https://trac.sagemath.org/ticket/26601

[sagetrac-git]

Changed commit from fbf07a6 to 2a481f1

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

2a481f1

Changed name

[egourgoulhon]

Description changed:

--- 
+++ 
@@ -1,4 +1,4 @@
-The parallelisation of the function `a.__mul__(a)` was only one test failing with `python3` in tensor/modules.
+The parallelisation of the function `a.__mul__(a)` in `src/sage/tensor/modules/comp.py` was only one test failing with `python3` in `src/sage/tensor`.
 Previously, with `python2.7`, to create the partial result we used 
 a list comprehension but now it fails.
 We have to replace it with a for loop.

[egourgoulhon]

comment:4

Thank you Marco!

I've checked the changes with both Python2 and Python3.
In particular, with Python3, sage -tp --long src/sage/tensor/ returns now "All tests passed!".

[egourgoulhon]

Reviewer: Eric Gourgoulhon

[vbraun]

Changed branch from public/manifolds/To_python3_parellisation_prob_in_tensor_comp to 2a481f1