Fixed typo introduced by shared code

dmenu.c

@@ -118,7 +118,7 @@ main(int argc, char *argv[]) {
 	if(!setlocale(LC_CTYPE, "") || !XSupportsLocale())
 		fputs("warning: no locale support\n", stderr);
 	if(!(dpy = XOpenDisplay(NULL)))
-		die("dwm: cannot open display\n");
+		die("dmenu: cannot open display\n");
 	screen = DefaultScreen(dpy);
 	root = RootWindow(dpy, screen);
 	sw = DisplayWidth(dpy, screen);