Fix old Pentax'es (K10D/K20D) not being recognized (march 2011 regression).
Fix old Pentax'es (K10D/K20D) not being recognized (march 2011 regression).

LebedevRI/rawspeed,mgehre/rawspeed,LebedevRI/rawspeed,mgehre/rawspeed,darktable-org/rawspeed,darktable-org/rawspeed,LebedevRI/rawspeed,klauspost/rawspeed,anarsoul/rawspeed,LebedevRI/rawspeed,darktable-org/rawspeed,anarsoul/rawspeed,anarsoul/rawspeed,klauspost/rawspeed,darktable-org/rawspeed,LebedevRI/rawspeed,darktable-org/rawspeed