Bug 746124 - Pull updates for path module from upstream node.

I don't think we need to review this since it's just pulls latest changes to path module from nodejs. If it's green on try:
https://tbpl.mozilla.org/?tree=Try&rev=d58022ab8c8d

It does fixes oranges https://bugzilla.mozilla.org/show_bug.cgi?id=746124#c6

So I'd be a+ on this to go in.