fixup! client_test: Add nmaster={1,2} to test matrix

Actually do test nmaster=2 case.

go/neo/client_test.go

@@ -447,9 +447,7 @@ func withNEOSrv(t *testing.T, f func(t *testing.T, nsrv NEOSrv), optv ...tOption
 
 	// TODO + all variants with nreplica=X, npartition=Y, ... ?
 
-
-	for _, nmaster := range []int{1, 1} {
-
+	for _, nmaster := range []int{1, 2} {
 		for _, ssl := range []bool{false, true} {
 			kind := fmt.Sprintf("M%d/", nmaster)
 			if ssl { kind += "ssl" } else { kind += "!ssl" }