selftests: net: lib: ignore possible errors

[ Upstream commit 7e0620bc ]

No need to disable errexit temporary, simply ignore the only possible
and not handled error.

Reviewed-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://lore.kernel.org/r/20240607-upstream-net-next-20240607-selftests-mptcp-net-lib-v1-1-e36986faac94@kernel.org


Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Stable-dep-of: 7965a7f3 ("selftests: net: lib: kill PIDs before del netns")
Signed-off-by: Sasha Levin <sashal@kernel.org>