Fix race condition in chown

[didactic-drunk]

Described in #9174

[straight-shoota]

While at it, could you perhaps switch the then and else branches to avoid the negated condition?
It's fine to merge either way.

[didactic-drunk]

I know this is extreme micro optimizing, but if's are assumed to be true by the CPU without additional hinting correct? So if x should contain the more likely branch making the current if better because follow_symlinks defaults to false.

If only there was a way to give hints to the compiler LIKELY/UNLIKELY, or possibly use unless as a CPU hinted not likely branch.

[straight-shoota]

I believe branch prediction is pretty useless at this point. On the odd chance this code ends up in a hot path, it won't make a difference when the next instruction is a costly syscall anyways.