settings: Update type for logout in media keys
settings: Update type for logout in media keys

This fixes the following error when trying to install the new
gnome-settings-daemon 3.34.0:
  Error parsing key "logout" in schema "org.gnome.settings-daemon.plugins.media-keys"
  as specified in override file "/usr/share/glib-2.0/schemas/50_eos-theme.gschema.override":
  0-2:can not parse as value of type 'as'. Ignoring override for
  this key.

https://phabricator.endlessm.com/T27676

endlessm/eos-theme