mate-screensaver: update to 1.22

### mate-screensaver 1.22.0

  * Translations update
  * Initialize Travis CI support
  * Make translatable the auth-username-label in lock-dialog-default.ui
  * mate-screensaver-command: Support unlocking (--unlock) the screensaver via CLI.
  * disable deprecation warnings for distcheck
  * fade: fix fade computation math
  * fix more GdkScreen related deprecations
  * gs-grab-x11: replace deprecated gdk_error_trap_push/pop
  * gs-visual-gl: replace deprecated gdk_error_trap_push/pop
  * Remove "monitor" pointer from debug information
  * lock-plug: Only scale lock-screen widgets on older versions of GTK
  * gs-lock-plug: avoid deprecated 'gdk_keymap_get_default'

(gutteridge)