xl/deleteObject: Support deleting special multipart object. (#1470)
xl/deleteObject: Support deleting special multipart object. (#1470)

Fixes #1452
aead/minio,krishnasrinivas/minio,aead/minio,harshavardhana/minio,aead/minio,koolhead17/minio,mf-00/newgo,vadmeste/minio,brendanashworth/minio,donatello/minio,minio/minio,dvstate/minio,harshavardhana/minio,dvstate/minio,jimjag/minio,koolhead17/minio,rushenn/minio,fwessels/minio,mkash32/minio,rushenn/minio,NitishT/minio,krisis/minio,brendanashworth/minio,aead/minio,harshavardhana/minio,krishnasrinivas/minio,balamurugana/minio,dutchcoders/minio,alexellis/minio,dvstate/minio,krishnasrinivas/minio-daily,NitishT/minio,aead/minio,minio/minio,abperiasamy/minio,NitishT/minio,dutchcoders/minio,jimjag/minio,harshavardhana/minio,krishnasrinivas/minio-daily,hackintoshrao/minio,aead/minio,aead/minio,jimjag/minio,rajivm/minio,luomeiqin/minio,fwessels/minio,luomeiqin/minio,abperiasamy/minio,dutchcoders/minio,donatello/minio,abperiasamy/minio,krishnasrinivas/minio,harshavardhana/minio,dvstate/minio,hackintoshrao/minio,balamurugana/minio,NitishT/minio,luomeiqin/minio,rushenn/minio,brendanashworth/minio,jimjag/minio,aead/minio,mf-00/newgo,krisis/minio,abperiasamy/minio,dutchcoders/minio,alexellis/minio,luomeiqin/minio,krishnasrinivas/minio,vadmeste/minio,brendanashworth/minio,harshavardhana/minio,fwessels/minio,hackintoshrao/minio,rajivm/minio,fwessels/minio,harshavardhana/minio,hackintoshrao/minio,mkash32/minio,harshavardhana/minio,rushenn/minio