Initialise buf.hello.

interface.c

@@ -335,6 +335,7 @@ interface_up(struct interface *ifp, int up)
             ifp->buf.size = 0;
             goto fail;
         }
+        ifp->buf.hello = -1;
 
         rc = resize_receive_buffer(mtu);
         if(rc < 0)

neighbour.c

@@ -109,6 +109,7 @@ find_neighbour(const unsigned char *address, struct interface *ifp)
     neigh->ifp = ifp;
     neigh->buf.buf = buf;
     neigh->buf.size = ifp->buf.size;
+    neigh->buf.hello = -1;
     neigh->buf.flush_interval = ifp->buf.flush_interval;
     neigh->buf.sin6.sin6_family = AF_INET6;
     memcpy(&neigh->buf.sin6.sin6_addr, address, 16);