Avoid warning for uninitialized member in OneDGridLeafIterator

enabled an automatic merge when the pipeline for 5e23465e succeeds

The CI-job debian:10 clang-7-libcpp-17 repeatedly failed for different MRs due to reasons that seem to be unrelated to the MR, but do always show up during the compilation while running python tests. See e.g. https://gitlab.dune-project.org/core/dune-grid/-/jobs/352172 where the actual error is:

ImportError: /duneci/modules/dune-common/build-cmake/dune-env/.cache/dune-py/python/dune/generated/hierarchicalgrid_aafc118db4a227d1c1e986789dc59e2d.so: undefined symbol: ZN4Dune12relativePathERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEES7

approved this merge request

unapproved this merge request

merged

mentioned in commit 1fe14aa7

resolved all threads