Instructions for deleting Guest user

Added a section to 'shell-guest-session' to mirror linked guide.

Link to related message on the ubuntu-doc mailing list:
https://lists.ubuntu.com/archives/ubuntu-doc/2014-January/018563.html

This bug was fixed in the package ubuntu-docs - 14.04.1

---------------
ubuntu-docs (14.04.1) trusty; urgency=low

  [ Kevin Godby ]
  * configure.in, html/Makefile, html/ubuntu.xsl, whats-new.page:
    - Bumped version number to 14.04.
  * Typo on printing-cancel-job.page fixed (LP: #1231655).

  [ Little Girl ]
  * ubuntu-help/C/check_status.sh:
    - Added the EXTINCT listing for status to display references to
      previous releases.
    - Added a section on how to use status tags.
    - Fixed the script so that it will find revision elements with stub
      attributes.
  * accounts-create.page:
    - Improved wording (LP: #1220971).
  * Improved structure and minor tweaking of many pages.

  [ Doug Smythies ]
  * ubuntu-help/Makefile.am:
    - Added missing .png files (LP: #1245031).
  * disk-capacity.page:
    - Clarify disk usage analyzer (LP: #1059535).
  * Link corrections so that yelp-check ids will pass.
  * display-dual-monitors.page:
    - Fixed 2 unmatched block elements: section html compile errors.
  * Some occurrences of GNOME only code and .png file requests removed
    (LP: #1232708).
  * PO files updated:
    - Exported the latest translations from Launchpad.
    - Four new languages: et, eu, tg, th.

  [ Benjamin Kerensa ]
  * Update of the MAINTAINERS file.
  * Minor tweaks.

  [ Gunnar Hjalmarsson ]
  * The group "Add & remove software" highlighted on index.page by
    creation of the guide page addremove.page. Related links tweaking.
  * shell-guest-session.page:
    - Added description of how you can disable the guest session
      feature (LP: #1076740).
  * Creation of prefs-language-install.page.
  * keyboard-layouts.page:
    - Rewritten to reflect the "System Settings -> Text Entry" design
      (LP: #1242626).
  * tips-specialchars.page:
    - Sections "Compose key" and "Input methods" removed.
  * debian/control:
    - Bump Standards-Version to 3.9.5.
  * Updated ubuntu-help.pot.

  [ Greg Beam ]
  * The "Online accounts" pages improved, including:
    - Grammar fixes on accounts-whyadd.page (LP: #1220983).
    - Removal of accounts-create.page (LP: #1220971).
    - System settings steps worded as on other pages (LP: #1268775).
  * addremove-install-synaptic.page:
    - Grammar fix (LP: #1222288).
  * Fixed validation errors (LP: #1268834).
  * Note style corrected (changed from "info" to "tip", LP: #1269100).

  [ Jeffery To ]
  * power-hibernate.page:
    - Instructions for re-enabling hibernation updated (LP: #1232814).

  [ Shaun McCance ]
  * html/ubuntu.xsl:
    - Link trail no longer needs override (LP: #1275818).
  * Changes to pass strict validation (LP: #1275866).
 -- Gunnar Hjalmarsson <email address hidden> Fri, 14 Feb 2014 18:07:00 +0100