openvswitch: drop unneeded newline

OVS_NLERR prints a newline at the end of the message string, so the
message string does not need to include a newline explicitly.  Done
using Coccinelle.

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>