add wl_abort private function

On many places in the code we use wl_log + abort or wl_log + assert(0).
Replace these with one call to wl_abort, so that we don't mix abort(),
assert(0) and we'll save few lines

Signed-off-by: Marek Chalupa <mchqwerty@gmail.com>
Reviewed-by: Derek Foreman <derekf@osg.samsung.com>

src/wayland-util.c

@@ -385,3 +385,15 @@ wl_log(const char *fmt, ...)
 	wl_log_handler(fmt, argp);
 	va_end(argp);
 }
+
+void
+wl_abort(const char *fmt, ...)
+{
+	va_list argp;
+
+	va_start(argp, fmt);
+	wl_log_handler(fmt, argp);
+	va_end(argp);
+
+	abort();
+}