system/chown : false check when uid or gid passed is NaN

[IDerr]

Hi,
When the uid or gid is nan :
if ((!options.uid || options.stat.uid === options.uid) && (!options.gid || options.stat.gid === options.gid))

!options.uid will return true

[5.DEBUG nikita/lib/chown] "Entering chown"
[6.INFO nikita/lib/chown] "stat.uid=0 uid=NaN stat.gid=0 gid=NaN"
[6.INFO nikita/lib/chown] "uidcheck=true gidCheck=true"
[6.INFO nikita/lib/chown] "Matching ownerships on 'mydir'"

Thanks for your work.

[wdavidw]

Do you feel like submitting a pull request, i'll be happy to review it ?