qt4-x11 - security update

This update fixes multiple security issues in the Qt library.

• CVE-2013-0254
  The QSharedMemory class uses weak permissions (world-readable and
  world-writable) for shared memory segments, which allows local users
  to read sensitive information or modify critical program data, as
  demonstrated by reading a pixmap being sent to an X server.
• CVE-2015-0295 / CVE-2015-1858 / CVE-2015-1859 / CVE-2015-1860
  Denial of service (via segmentation faults) through crafted
  images (BMP, GIF, ICO).