Linter-induced code refactoring, run round 2. (#360)

Run more linters in the gometalinter, i.e. deadcode, megacheck,
nakedret, dup.

More consistent code formatting, remove two dead functions, eliminate
naked a bunch of naked returns, refactor a few functions to avoid code
duplication.

pkg/util/patroni/patroni.go

@@ -47,7 +47,7 @@ func apiURL(masterPod *v1.Pod) string {
 	return fmt.Sprintf("http://%s:%d", masterPod.Status.PodIP, apiPort)
 }
 
-func (p *Patroni) httpPostOrPatch(method string, url string, body *bytes.Buffer) error {
+func (p *Patroni) httpPostOrPatch(method string, url string, body *bytes.Buffer) (err error) {
 	request, err := http.NewRequest(method, url, body)
 	if err != nil {
 		return fmt.Errorf("could not create request: %v", err)
@@ -59,7 +59,16 @@ func (p *Patroni) httpPostOrPatch(method string, url string, body *bytes.Buffer)
 	if err != nil {
 		return fmt.Errorf("could not make request: %v", err)
 	}
-	defer resp.Body.Close()
+	defer func() {
+		if err2 := resp.Body.Close(); err2 != nil {
+			if err != nil {
+				err = fmt.Errorf("could not close request: %v, prior error: %v", err2, err)
+			} else {
+				err = fmt.Errorf("could not close request: %v", err2)
+			}
+			return
+		}
+	}()
 
 	if resp.StatusCode != http.StatusOK {
 		bodyBytes, err := ioutil.ReadAll(resp.Body)
@@ -83,6 +92,7 @@ func (p *Patroni) Switchover(master *v1.Pod, candidate string) error {
 }
 
 //TODO: add an option call /patroni to check if it is necessary to restart the server
+
 //SetPostgresParameters sets Postgres options via Patroni patch API call.
 func (p *Patroni) SetPostgresParameters(server *v1.Pod, parameters map[string]string) error {
 	buf := &bytes.Buffer{}