Use update() instead of init() in neighbor example

Signed-off-by: Brenden Blanco <bblanco@plumgrid.com>
diff --git a/examples/tc_neighbor_sharing.c b/examples/tc_neighbor_sharing.c
index 6ba7d35..87ea0ea 100644
--- a/examples/tc_neighbor_sharing.c
+++ b/examples/tc_neighbor_sharing.c
@@ -53,7 +53,7 @@
     u32 sip = ip->src;
     struct ipkey key = {.client_ip=sip};
     int val = 1;
-    learned_ips.lookup_or_init(&key, &val);
+    learned_ips.update(&key, &val);
     goto EOP;
   }
 EOP: