Fix logic checking the ignore_lostfound argument.

[clopez]

• Check with:

  $ unset ilost; test -n "$ilost" -a "$ilost" != 0 && echo "setting ignore_lostfound="

  $ ilost=0; test -n "$ilost" -a "$ilost" != 0 && echo "setting ignore_lostfound="

  $ ilost=1; test -n "$ilost" -a "$ilost" != 0 && echo "setting ignore_lostfound=" setting ignore_lostfound=

[clopez]

This was erroneous. Check the new pull https://github.com/linux-vserver/util-vserver/pull/7 for the fixed version