Martin Lueders requested to merge vec_gather_fix into develop Dec 02, 2019

Description

This MR fixes a problem of passing an uninitialized pointer to vev_gather, leading to run-time errors on some compilers and valgrind errors.

News snippet

Uninitialized variable in vec_gather fixed.

Checklist

I have checked that my code follows the Octopus coding standards
I have added tests for all the new features added in this request.