Lock leakage on rename if vop->vop_rename is NULL (kern/107439)

[Mikolaj Golub]

Hi,

Could somebody look at kern/107439? Although the pr is closed the issue still
persists: if a file system does not provide vop_rename the vop_bypass() is
called and the vnods, which are expected to be unlocked in VOP_RENAME(), are
left locked.

I have attached there the patch that solves the problem but I am not confident
about the solution.

-- 
Mikolaj Golub