Merge branch 'lsfd--sysvipc-shmem' of https://github.com/masatake/util-linux

Merge branch 'lsfd--sysvipc-shmem' of https://github.com/masatake/util-linux

* 'lsfd--sysvipc-shmem' of https://github.com/masatake/util-linux:
  tests: (lsfd) add a case for testing SOURCE column for SysV shmem mappings
  tests: (mkfds) add a factory to make SysV shmem
  lsfd: add tmpfs as source of sysvipc to the the nodev_table
  lsfd: initialize pagesize in an earlier stage
  lsfd: add "nsfs" to the nodev_table to fill SOURCE column for nsfs files
  lsfd: add a helper function for adding a nodev to the nodev_table
  lsfd: add a whitespace
  lsfd: write more about nsfs in comment