Security update for cinnamon (moderate)

This update for cinnamon fixes the following issues:

Security issue fixed:

• CVE-2018-13054: Fix symlink attack vulnerability (boo#1083067).

Bug fixes:

• Update to version 3.4.6 (changes since 3.4.4):
  • osdWindow.js: Always check the theme node on first showing - an
    actor’s width isn’t necessarily filled if it hasn’t been explicitly
    set, causing the first few activations of the OSD to not show an
    accurate level bar.
  • cs_default: Fix an incorrect button label (but preserve translations).
  • main.js: Remove an obsolete Meta enum member reference.
  • workspace.js: Use our normal prototype init method.
  • workspace.js: Initalise WindowClone._zoomStep to 0.
  • slideshow-applet: Fix a translation.
  • cs_themes.py: Create the file "~/.icons/default/index.theme" and set
    the selected cursor theme inside of it. This ensures other (non-gtk)
    applications end up using the same theme (though they are required to
    be restarted for these changes to take effect).
  • keyboard-applet: Applet icon vanishes when moved in edit mode.
  • cinnamon-json-makepot: Add keyword option, change language used by
    xgettext to JavaScript.
  • expoThumbnail: Correct a couple of calls with mismatched argument
    counts.
  • window-list: Set AppMenuButtons unreactive during panel edit mode.
  • panel-launchers: Set PanelAppLaunchers unreactive during panel edit
    mode.
  • windows-quick-list: Fix argument warning.
  • Fix a reference to undefined actor._delegate warning.
  • ui/environment: Handle undefined actors in
    containerClass.prototype.add.
  • ui/cinnamonDBus: Handle null xlet objects in
    CinnamonDBus.highlightXlet.
  • deskletManager: Initialise some variables and remove the variables
    that were initialised, probable typo