Log Message:
cups-filters: Update print/cups-filters to 1.21.5

pkgsrc changes:
 - Remove no more needed patch for poppler 0.71.0
 - Add a reference to upstream issue regarding (temporary) opvp
   disabled support

Changes:
1.21.5
------
 - cups-browsed: We cannot reliably determine whether a CUPS
   queue is temporary, so we apply the procedure to make a
   temporary queue permanent to any unshared queue (Debian bugs
   #910882, #905850, #908604).
 - pdftoraster, pdftopdf, pdftoijs, pdftoopvp: Do not use the
   Poppler-specific "GBool", "gFalse", "gTrue" any \ 
more, as
   Poppler has switched to standard "bool", "false", \ 
"true" in
   version 0.71.0 (Issue #69).