krdb: do not crash on file system problems
notably EACCESS may get thrown here and crash startplasma, instead use the error_code overloads and skip over problems https://errors-eval.kde.org/organizations/kde/issues/323
notably EACCESS may get thrown here and crash startplasma, instead use the error_code overloads and skip over problems https://errors-eval.kde.org/organizations/kde/issues/323
mentioned in commit d747d3c0