* 'github-issue-3442' of https://github.com/masatake/util-linux:
tests: (lsns) verify NETNSID column for namespaces with no process running
lsns: make "-Q NETNSID ..." work even if NETNSID column is not enabled
lsns: show NETNSID for namespaces with no process running
lsns: (refactor) generalize the code for collecting netnsid information