Fixes https://github.com/minio/minio/issues/4320 (#4332)
Fixes https://github.com/minio/minio/issues/4320 (#4332)

- Add description for error ErrBucketAlreadyExists
vadmeste/minio,aead/minio,vadmeste/minio,balamurugana/minio,rushenn/minio,balamurugana/minio,harshavardhana/minio,NitishT/minio,harshavardhana/minio,aead/minio,krishnasrinivas/minio,krishnasrinivas/minio,NitishT/minio,abperiasamy/minio,dvstate/minio,harshavardhana/minio,fwessels/minio,fwessels/minio,krishnasrinivas/minio,aead/minio,donatello/minio,harshavardhana/minio,krishnasrinivas/minio,aead/minio,fwessels/minio,aead/minio,minio/minio,jimjag/minio,dvstate/minio,abperiasamy/minio,harshavardhana/minio,aead/minio,jimjag/minio,rushenn/minio,aead/minio,jimjag/minio,NitishT/minio,jimjag/minio,krisis/minio,abperiasamy/minio,fwessels/minio,aead/minio,minio/minio,harshavardhana/minio,donatello/minio,NitishT/minio,abperiasamy/minio,rushenn/minio,harshavardhana/minio,harshavardhana/minio,dvstate/minio,krisis/minio,dvstate/minio,rushenn/minio