fix for Coverity CID 1173035:  Uninitialized scalar field  (UNINIT_CTOR)

@luizirber @camillescott @ctb merge requested

- [x] Is it mergable
- [x] Did it pass the tests?
- [NA] If it introduce new functionality in scripts/ is it tested?
  Check for code coverage.
- [x] Is it well formatted? Look at `pep8`/`pylint`, `cppcheck`, and
  `make doc` output. Use `autopep8` and `astyle -A10` if needed.
- [x] Is it documented in the Changelog?