Send resume signal when built with systemd and using pm-utils suspend

This case was apparently overlooked when adding systemd support.

Signed-off-by: Jan Alexander Steffens (heftig) <jan.steffens@gmail.com>
Signed-off-by: Richard Hughes <richard@hughsie.com>

src/linux/up-backend.c

@@ -603,10 +603,11 @@ gboolean
 up_backend_emits_resuming (UpBackend *backend)
 {
 #ifdef HAVE_SYSTEMD
-	return TRUE;
-#else
-	return FALSE;
+	if (sd_booted ())
+		return TRUE;
+	else
 #endif
+	return FALSE;
 }
 
 /**