Fix handling files at leaf attempting disk.ListDir() (#6155)
Fix handling files at leaf attempting disk.ListDir() (#6155)

Return an ignorable error upon readDir() failure on
a file.
krisis/minio,aead/minio,aead/minio,vadmeste/minio,fwessels/minio,harshavardhana/minio,NitishT/minio,krishnasrinivas/minio,harshavardhana/minio,fwessels/minio,harshavardhana/minio,NitishT/minio,balamurugana/minio,jimjag/minio,donatello/minio,NitishT/minio,krishnasrinivas/minio,fwessels/minio,krishnasrinivas/minio,harshavardhana/minio,krishnasrinivas/minio,jimjag/minio,harshavardhana/minio,aead/minio,aead/minio,aead/minio,jimjag/minio,krisis/minio,harshavardhana/minio,fwessels/minio,harshavardhana/minio,aead/minio,NitishT/minio,balamurugana/minio,aead/minio,minio/minio,jimjag/minio,minio/minio,harshavardhana/minio,vadmeste/minio,aead/minio,donatello/minio