Log Message:
mate-netbook: update to 1.21.0

Change log:

  * Translations update
  * avoid deprecated 'gdk_error_trap_push/pop/pop_ignored' and 'gdk_flush'
  * disable deprecation warnings for distcheck
  * tomboykeybinder: avoid deprecated 'gdk_keymap_get_default'
  * transifex: update config with branch specific resoures