CUPS commandtops filter added (and then removed) to non-PostScript printers

Issue

• When modifying a printer's PPD to change the default page size, CUPS removes the line "Filter application/vnd.cups-command 0 commandtops" from /etc/cups/printers.conf that was automatically when the print queue was created.
• CUPS adds a filter to convert CUPS command format into PostScript when non-PostScript printers are added if the PPD file for the printer contains a filter that converts PostScript into another format for printing. CUPS then later removes that filter if the PPD file is modified when a default option is changed.