buildroot

netcat: force-remove nc link before install

The nc -> netcat symlink is not created if nc exists already, e.g.
from busybox.

For netcat itself this is not needed, it is always installed.

Cc: Carlos Santos <casantos@datacom.ind.br>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>