Merge branch 'selftests-mptcp-use-net-lib-sh-to-manage-netns'

Matthieu Baerts says:

====================
selftests: mptcp: use net/lib.sh to manage netns

The goal of this series is to use helpers from net/lib.sh with MPTCP
selftests.

- Patches 1 to 4 are some clean-ups and preparation in net/lib.sh:

  - Patch 1 simplifies the code handling errexit by ignoring possible
    errors instead of disabling errexit temporary.

  - Patch 2 removes the netns from the list after having cleaned it, not
    to try to clean it twice.

  - Patch 3 removes the 'readonly' attribute for the netns variable, to
    allow using the same name in local variables.

  - Patch 4 removes the local 'ns' var, not to conflict with the global
    one it needs to setup.

- Patch 5 uses helpers from net/lib.sh to create and delete netns in
  MPTCP selftests.

- Patch 6 uses wait_local_port_listen helper from net/net_helper.sh.
====================

Link: https://lore.kernel.org/r/20240607-upstream-net-next-20240607-selftests-mptcp-net-lib-v1-0-e36986faac94@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>