Force integer division for truncation of stdout/stderr in dogwrap

[glasnt]

👋

Observed behaviour:

When dogwrap runs in a Python 3 environment with submit_mode=all, and there is both stdout and stderr, the following error occurred:

    ...
    top_third=text[:max_len / 3],
TypeError: slice indices must be integers or None or have an __index__ method

Cause:

This is because in Python 3, int / int no longer returns an int, it returns a float. And floats are invalid index values.

Solution:

This integer division functionality can be forced by using // rather than / in both Python 3 and Python 2. (Tested in Python 2.7.12, Python 3.5.2; operator introduced in Python 2.2+ (PEP238)

This change has only been tested manually, because it doesn't appear dogwrap is currently being tested (please correct me if I'm wrong)

[glasnt]

Oops, should have checked the existing PRs 😕

This is a partial duplicate of #260, but this PR includes a third change, ensuring all instances of division are forced to integer division

[thisiscab]

Good catch on the third change! :)

[yannmh]

@glasnt @cabouffard thanks a lot for the fix 🙇