Log Message:
caja: update to version 1.21.4

Change log:

  * update translations
  * Avoid deprecated g_type_class_add_private under src
  * Fix incompatible pointer types
  * Avoid deprecated g_type_class_add_private under src
  * Avoid deprecated g_type_class_add_private under libcaja-private
  * Enable Travis CI
  * Fix compile warning
  * Let file size units follow the users preference
  * Fixed the value of 6 month and 1 year.
  * Support querying files by modification time and size
  * Avoid deprecated g_type_class_add_private
  * Update copyright to 2019
  * CajaApplication: avoid deprecated 'g_type_class_add_private'
  * caja-menu: avoid deprecated 'g_type_class_add_private'
  * [eel][libegg] Use G_DEFINE_TYPE_WITH_PRIVATE macro
  * configure.ac: Add check for PKG_CONFIG being set.
  * caja-application: Check for smclient before trying to load session
  * [eel] Avoid deprecated g_type_class_add_private
  * [libegg] Avoid deprecated g_type_class_add_private
  * [libcaja-private] Re-check file MIME type before picking an application.
  * [file-manager] Fix apparent bug in context menu updating code.
  * Revert "fm-directory-view.c:  Decrease minimum update interval."
  * Fix: weird item in bookmarks if the folder was removed
  * Minor code-quality enhancements
  * Forgot to initialize is_backup field
  * Change show/hide backup files shortcut
  * Remove useless comments, correct description string
  * Skip hidden files only, not backups
  * Add independent show/hide backup files
  * deleting unused nautilus icon
  * caja-progress-info: new behavior with notifications:
  * caja-progress-info: show notifications with the gsettings key:
  * move appdata to metainfo directory
  * disable deprecation warnings for distcheck
  * caja-places-sidebar: replace two other uses of g_drive_poll_for_media_finish
  * Fix segfault on stopping USB hard drives
  * caja-bookmark: Fix memory leak
  * fm-properties-window: Fix memory leaks
  * caja-desktop-link-monitor: Fix memory leak
  * eel-gtk-extensions: Fix memory leaks