Log Message:
Update to 0.11.7 (security/bugfix release). Changes since 0.11.6:

Security fixes:

    * Fixed a ticket validation issue that would allow unauthorized
      users to modify the status and resolution of a ticket (#8884)

Performance improvements:

    * Trac wiki had some trouble handling very long unicode words
      (#9025)

    * Full text search was very slow if lots of custom fields were
      used (#8935)

Bug fixes:

    * Fixed a race condition that could lead to the destruction of the
      trac.ini file (#8623)

    * Fixed creation of new milestone which could have been a rename
      if performed after a name clash has been detected (#8816)

    * Fixed display of value 0 in report cells (#7512)