camput: use Errorf to print critical errors even when non-verbose

http://camlistore.org/issue/524

Change-Id: Ied24471288ea459785291281afa7316a257b6884

cmd/camput/camput.go

@@ -100,7 +100,7 @@ func initUploader() {
 
 func handleResult(what string, pr *client.PutResult, err error) error {
 	if err != nil {
-		log.Printf("Error putting %s: %s", what, err)
+		cmdmain.Errorf("Error putting %s: %s\n", what, err)
 		cmdmain.ExitWithFailure = true
 		return err
 	}

pkg/cmdmain/cmdmain.go

@@ -290,7 +290,7 @@ func Main() {
 	if err != nil {
 		if !ExitWithFailure {
 			// because it was already logged if ExitWithFailure
-			log.Printf("Error: %v", err)
+			Errorf("Error: %v\n", err)
 		}
 		Exit(2)
 	}