Comment 13 for bug 55283

I think I found something.
On my system the file /etc/cups/pstoraster contains the line you need and comes installed with gs-esp:
application/vnd.cups-postscript application/vnd.cups-raster 100 pstoraster

Do you have this file? Please give the output of the following commands:
$ ls -l /etc/cups/*.types /etc/cups/*.convs
$ grep -H "application/vnd.cups-raster" /etc/cups/*.types /etc/cups/*.convs | grep pstoraster
$ grep -H "application/vnd.cups-command" /etc/cups/*.types /etc/cups/*.convs

Why do you have both gs-afpl, gs-gpl and gs-esp installed? You only need gs-esp for printing with CUPS.