packet: Add missing break in ssh_packet_incoming_filter()

CID 1396239

Signed-off-by: Andreas Schneider <asn@cryptomilk.org>
(cherry picked from commit fe618a35dc)

src/packet.c

@@ -308,6 +308,7 @@ static enum ssh_packet_filter_result_e ssh_packet_incoming_filter(ssh_session se
             (session->dh_handshake_state != DH_STATE_FINISHED))
         {
             rc = SSH_PACKET_DENIED;
+            break;
         }
 
         rc = SSH_PACKET_ALLOWED;