rpc: remove num assets from universe Info call

The call it just used as a quick sanity check, so doesn't need to depend
on a potentially expensive db transaction.

Fixes #643

itest/universe_test.go

@@ -458,7 +458,7 @@ func testUniverseFederation(t *harnessTest) {
 	// Test the content of the universe info call.
 	info, err := bob.Info(ctxt, &unirpc.InfoRequest{})
 	require.NoError(t.t, err)
-	require.EqualValues(t.t, 1, info.NumAssets)
+	require.NotZero(t.t, info.RuntimeId)
 
 	// We'll now make two new assets with Bob, and ensure that the state is
 	// properly pushed to the main node which is a part of the federation.

rpcserver.go

@@ -3716,14 +3716,8 @@ func (r *rpcServer) InsertProof(ctx context.Context,
 func (r *rpcServer) Info(ctx context.Context,
 	_ *unirpc.InfoRequest) (*unirpc.InfoResponse, error) {
 
-	universeStats, err := r.cfg.UniverseStats.AggregateSyncStats(ctx)
-	if err != nil {
-		return nil, err
-	}
-
 	return &unirpc.InfoResponse{
 		RuntimeId: r.cfg.RuntimeID,
-		NumAssets: universeStats.NumTotalAssets,
 	}, nil
 }