Update print/cups-filters to 1.6.0.

Changes:
CHANGES IN V1.6.0
	- cups-browsed: Fixed use of CUPS domain socket, both
	  detection during build process and permission check at
	  runtime.
	- foomatic-rip: Fixed buffer overflow when reading environment
	  variables CUPS_FONTPATH, CUPS_DATADIR, and GS_LIB (Bug
	  #1336).
	- beh: Introduced beh, the Backend Error Handler, a wrapper
	  backend to make handling of backend errors more
	  configurable. This backend is a C re-write of the beh
	  backend written in Perl which was part of the former
	  foomatic-filters package. Several people asked for beh
	  getting moved to cups-filters.
	- braille: Make image printing working also if ImageMagick
	  generates formatted images without header.
	- braille: If the user does not select a Braille translation,
	  let the embosser do the translation.
	- cups-browsed: Added version info to help screen and start-up
	  in debug mode, call help screen also via "--version" option.
	- cups-browsed: Minor improvements in help screen and man
          page.


(leot)