Deduplicate apk url code

cmd/fdroidcl/download.go

@@ -25,7 +25,7 @@ func runDownload(args []string) {
 	apps := findApps(args)
 	for _, app := range apps {
 		apk := app.CurApk
-		url := fmt.Sprintf("%s/%s", apk.Repo.URL, apk.ApkName)
+		url := apk.URL()
 		path := apkPath(apk.ApkName)
 		if err := downloadEtag(url, path, apk.Hash.Data); err != nil {
 			log.Fatalf("Could not download '%s': %v", app.ID, err)

cmd/fdroidcl/install.go

@@ -26,7 +26,7 @@ func runInstall(args []string) {
 	paths := make([]string, len(apps))
 	for i, app := range apps {
 		apk := app.CurApk
-		url := fmt.Sprintf("%s/%s", apk.Repo.URL, apk.ApkName)
+		url := apk.URL()
 		path := apkPath(apk.ApkName)
 		if err := downloadEtag(url, path, apk.Hash.Data); err != nil {
 			log.Fatalf("Could not download '%s': %v", app.ID, err)

index.go

@@ -158,6 +158,10 @@ type Apk struct {
 	Repo    *Repo
 }
 
+func (a *Apk) URL() string {
+	return fmt.Sprintf("%s/%s", a.Repo.URL, a.ApkName)
+}
+
 type appList []App
 
 func (al appList) Len() int           { return len(al) }