During auth generation, create directory if it does not exist.
During auth generation, create directory if it does not exist.

Addresses issue #902

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