files: Dump NFS silly-rename files as linked-remap always

We cannot distinguish ghost files from linked-remap for NFS.
Link count is never 0 on such files and any positive value of
it doesn't mean, that the file will stay in place after we
terminate all tasks we dump -- they can hold multiple unlinked
links on the same file and they all will be delayed-unlined.

Checkinf file path doesn't work as well -- silly-rename files
remain visible by VFS, though they shouldn't :(

Fortunatelly, NFS allows creation of additional likns on such
files, so we just create linked remap for such files.

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>