all: fix golangci-lint errors

These erroneously blocked a recent PR, which I fixed by simply
re-running CI. But we might as well fix them anyway.
These are mostly `printf` to `print` and a couple of `!=` to `!Equal()`

Updates #cleanup

Signed-off-by: Will Norris <will@tailscale.com>

cmd/addlicense/main.go

@@ -18,12 +18,12 @@ var (
 )
 
 func usage() {
-	fmt.Fprintf(os.Stderr, `
+	fmt.Fprint(os.Stderr, `
 usage: addlicense -file FILE <subcommand args...>
 `[1:])
 
 	flag.PrintDefaults()
-	fmt.Fprintf(os.Stderr, `
+	fmt.Fprint(os.Stderr, `
 addlicense adds a Tailscale license to the beginning of file.
 
 It is intended for use with 'go generate', so it also runs a subcommand,

cmd/k8s-operator/proxy.go

@@ -311,7 +311,7 @@ func (h *apiserverProxy) addImpersonationHeadersAsRequired(r *http.Request) {
 
 	// Now add the impersonation headers that we want.
 	if err := addImpersonationHeaders(r, h.log); err != nil {
-		log.Printf("failed to add impersonation headers: " + err.Error())
+		log.Print("failed to add impersonation headers: ", err.Error())
 	}
 }
 

cmd/tailscale/cli/risks.go

@@ -77,7 +77,7 @@ func presentRiskToUser(riskType, riskMessage, acceptedRisks string) error {
 	for left := riskAbortTimeSeconds; left > 0; left-- {
 		msg := fmt.Sprintf("\rContinuing in %d seconds...", left)
 		msgLen = len(msg)
-		printf(msg)
+		printf("%s", msg)
 		select {
 		case <-interrupt:
 			printf("\r%s\r", strings.Repeat("x", msgLen+1))

cmd/tsconnect/tsconnect.go

@@ -53,12 +53,12 @@ func main() {
 }
 
 func usage() {
-	fmt.Fprintf(os.Stderr, `
+	fmt.Fprint(os.Stderr, `
 usage: tsconnect {dev|build|serve}
 `[1:])
 
 	flag.PrintDefaults()
-	fmt.Fprintf(os.Stderr, `
+	fmt.Fprint(os.Stderr, `
 
 tsconnect implements development/build/serving workflows for Tailscale Connect.
 It can be invoked with one of three subcommands: