Format error by value

- Use `%v` verb to format errors.
- Give `param` constant in portallocator some better name.

Signed-off-by: Michal Minar <miminar@redhat.com>

api/client/commands.go

@@ -912,7 +912,7 @@ func (cli *DockerCli) CmdInspect(args ...string) error {
 		obj, _, err := readBody(cli.call("GET", "/containers/"+name+"/json", nil, false))
 		if err != nil {
 			if strings.Contains(err.Error(), "Too many") {
-				fmt.Fprintf(cli.err, "Error: %s", err.Error())
+				fmt.Fprintf(cli.err, "Error: %v", err)
 				status = 1
 				continue
 			}
@@ -2787,7 +2787,7 @@ func (cli *DockerCli) CmdStats(args ...string) error {
 	for _, c := range cStats {
 		c.mu.Lock()
 		if c.err != nil {
-			errs = append(errs, fmt.Sprintf("%s: %s", c.Name, c.err.Error()))
+			errs = append(errs, fmt.Sprintf("%s: %v", c.Name, c.err))
 		}
 		c.mu.Unlock()
 	}

api/common.go

@@ -104,7 +104,7 @@ func FormGroup(key string, start, last int) string {
 func MatchesContentType(contentType, expectedType string) bool {
 	mimetype, _, err := mime.ParseMediaType(contentType)
 	if err != nil {
-		log.Errorf("Error parsing media type: %s error: %s", contentType, err.Error())
+		log.Errorf("Error parsing media type: %s error: %v", contentType, err)
 	}
 	return err == nil && mimetype == expectedType
 }

api/server/server.go

@@ -135,7 +135,7 @@ func httpError(w http.ResponseWriter, err error) {
 	}
 
 	if err != nil {
-		log.Errorf("HTTP Error: statusCode=%d %s", statusCode, err.Error())
+		log.Errorf("HTTP Error: statusCode=%d %v", statusCode, err)
 		http.Error(w, err.Error(), statusCode)
 	}
 }
@@ -1123,7 +1123,7 @@ func postContainersCopy(eng *engine.Engine, version version.Version, w http.Resp
 	job.Stdout.Add(w)
 	w.Header().Set("Content-Type", "application/x-tar")
 	if err := job.Run(); err != nil {
-		log.Errorf("%s", err.Error())
+		log.Errorf("%v", err)
 		if strings.Contains(strings.ToLower(err.Error()), "no such id") {
 			w.WriteHeader(http.StatusNotFound)
 		} else if strings.Contains(err.Error(), "no such file or directory") {