Add a better error message on an invalid node

Change-Id: I2f9520da9619be997c94217e4258a370ef56be7f
Signed-off-by: Austin Schuh <austin.schuh@bluerivertech.com>
diff --git a/aos/network/message_bridge_server_lib.cc b/aos/network/message_bridge_server_lib.cc
index 5d7cdde..0bf9054 100644
--- a/aos/network/message_bridge_server_lib.cc
+++ b/aos/network/message_bridge_server_lib.cc
@@ -567,7 +567,10 @@
           node_index = channel_state->NodeConnected(
               connect->node(), message->header.rcvinfo.rcv_assoc_id,
               channel_index, &server_, monotonic_now, &reconnected_);
-          CHECK_NE(node_index, -1);
+          CHECK_NE(node_index, -1)
+              << ": Failed to find node "
+              << aos::FlatbufferToJson(connect->node()) << " for connection "
+              << aos::FlatbufferToJson(connect);
           matched = true;
           break;
         }