[OE-core] [PATCH] runqemu-export-rootfs: don't change RPC ports

[Cody P Schafer]

> The result of this is that trying to mount filesystems exported by
> runqemu-export-rootfs in modern kernels (at least in 4.2 and later, and
> probably more like 2.6.20 and later) doesn't actually work.

To clarify, when using nfsroot with the current kernel & unfsd
options, my boot stops, waits for the nfs root to appear, and then
times out. When trying to mount normally (ie: via `mount -t nfs` of a
very recent vintage in arch-linux), I get immediate "protocol family
not supported" errors.

With this change, both mount methods (nfsroot with new kernel options
and normally mount) work without issue.

> I'm honestly not sure how anyone was using this for nfsroot support.
> Maybe an initramfs with a version of nfs-utils that could handle the
> mountprog/nfsprog option was in use? Not sure.

Or is there some yocto kernel patch to enable support for it? I'm
running a custom kernel.