Log Message:
mate-desktop: update to 1.22.1

### mate-desktop 1.22.1

  * Translations update
  * Use mate-desktop icon instead of mate for mate-about
  * Use radial gradient (Blur 13.9%, Opacity 73.4%) for MATE logo shadow
  * mate-thumbnail-pixbuf-utils: Fix division by zero
  * mate-bg: Fix memory leak
  * GEN png icons from hicolor_apps_scalable_mate.svg
  * Make translatable the program name in mate about dialog
  * Make translatable the copyright info in mate about dialog
  * [Security] Use 'g_strlcpy' instead of 'strcpy'
  * [Security] test-ditem: Use 'g_strlcat' instead of 'strcat'