Use decimal verb for int in fmt format

This commit corrects a test error message which had been using a string
verb for an int value (breaks under 1.10).

Signed-off-by: John McCabe <[email protected]>

Author: johnmccabe

config/config_test.go

@@ -108,7 +108,7 @@ func Test_PortOverride(t *testing.T) {
 	}
 
 	if actual.TCPPort != 8081 {
-		t.Errorf("Want %s. got: %s", 8081, actual.TCPPort)
+		t.Errorf("Want %d. got: %d", 8081, actual.TCPPort)
 	}
 }