fix #5268: ignored cache may persist in DB
fix #5268: ignored cache may persist in DB

SammysHP/cgeo,matej116/cgeo,S-Bartfast/cgeo,Bananeweizen/cgeo,mucek4/cgeo,tobiasge/cgeo,mucek4/cgeo,mucek4/cgeo,superspindel/cgeo,Bananeweizen/cgeo,superspindel/cgeo,tobiasge/cgeo,cgeo/cgeo,kumy/cgeo,matej116/cgeo,pstorch/cgeo,SammysHP/cgeo,cgeo/cgeo,S-Bartfast/cgeo,auricgoldfinger/cgeo,cgeo/cgeo,rsudev/c-geo-opensource,kumy/cgeo,S-Bartfast/cgeo,samueltardieu/cgeo,auricgoldfinger/cgeo,cgeo/cgeo,samueltardieu/cgeo,kumy/cgeo,auricgoldfinger/cgeo,rsudev/c-geo-opensource,SammysHP/cgeo,Bananeweizen/cgeo,pstorch/cgeo,tobiasge/cgeo,rsudev/c-geo-opensource,matej116/cgeo,samueltardieu/cgeo,pstorch/cgeo,superspindel/cgeo