cmd, lib: Fix ineffectual assignments (ineffasign) and comment spelling

GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/3405

lib/config/config.go

@@ -105,7 +105,9 @@ func ReadJSON(r io.Reader, myID protocol.DeviceID) (Configuration, error) {
 		return Configuration{}, err
 	}
 
-	err = json.Unmarshal(bs, &cfg)
+	if err := json.Unmarshal(bs, &cfg); err != nil {
+		return Configuration{}, err
+	}
 	cfg.OriginalVersion = cfg.Version
 
 	if err := cfg.prepare(myID); err != nil {

lib/config/config_test.go

@@ -549,6 +549,9 @@ func TestPullOrder(t *testing.T) {
 	t.Logf("%s", buf.Bytes())
 
 	cfg, err = ReadXML(buf, device1)
+	if err != nil {
+		t.Fatal(err)
+	}
 	wrapper = Wrap("testdata/pullorder.xml", cfg)
 	folders = wrapper.Folders()