refactor: simplify ListenAndServe error handling

From https://golang.org/pkg/net/http/#ListenAndServe:
"ListenAndServe always returns a non-nil error."

Author: php-coder

examples/go/app.go

@@ -10,8 +10,7 @@ func main() {
 	registerRoutes(r)
 
 	fmt.Println("Listen on 3000")
-	if err := http.ListenAndServe(":3000", r); err != nil {
-		fmt.Fprintf(os.Stderr, "ListenAndServe failed: %v\n", err)
-		os.Exit(1)
-	}
+	err := http.ListenAndServe(":3000", r)
+	fmt.Fprintf(os.Stderr, "ListenAndServe failed: %v\n", err)
+	os.Exit(1)
 }

src/templates/app.go

@@ -10,8 +10,7 @@ func main() {
 	registerRoutes(r)
 
 	fmt.Println("Listen on 3000")
-	if err := http.ListenAndServe(":3000", r); err != nil {
-		fmt.Fprintf(os.Stderr, "ListenAndServe failed: %v\n", err)
-		os.Exit(1)
-	}
+	err := http.ListenAndServe(":3000", r)
+	fmt.Fprintf(os.Stderr, "ListenAndServe failed: %v\n", err)
+	os.Exit(1)
 }