Use "if (expr) { } else" as I meant to in the first place. The other form

Use "if (expr) { } else" as I meant to in the first place. The other form

	* glib/gmessages.h: Use "if (expr) { } else" as I meant to in the
	first place. The other form can trigger warnings in some compilers
	that suspect a ";" after "if (expr)" is an error.