posix: Disk free verification should have relaxed handling of inodes. (#2431)
posix: Disk free verification should have relaxed handling of inodes. (#2431)

Some filesystems do not implement a way to provide total inodes available, instead inodes
are allocated based on available disk space. For example CephFS, StoreNext CVSFS, AzureFile
driver. Allow for the available disk to be separately validate and we will validate inodes
only if the total inodes are provided by the underlying filesystem.

Fixes #2364
krisis/minio,dvstate/minio,brendanashworth/minio,vadmeste/minio,brendanashworth/minio,abperiasamy/minio,krishnasrinivas/minio,jimjag/minio,aead/minio,jimjag/minio,harshavardhana/minio,jimjag/minio,aead/minio,donatello/minio,luomeiqin/minio,alexellis/minio,abperiasamy/minio,rushenn/minio,hackintoshrao/minio,jimjag/minio,krishnasrinivas/minio,harshavardhana/minio,harshavardhana/minio,koolhead17/minio,fwessels/minio,aead/minio,brendanashworth/minio,balamurugana/minio,NitishT/minio,koolhead17/minio,abperiasamy/minio,alexellis/minio,aead/minio,luomeiqin/minio,dutchcoders/minio,vadmeste/minio,hackintoshrao/minio,balamurugana/minio,aead/minio,dvstate/minio,hackintoshrao/minio,dutchcoders/minio,aead/minio,fwessels/minio,fwessels/minio,dvstate/minio,rushenn/minio,luomeiqin/minio,donatello/minio,dvstate/minio,rushenn/minio,fwessels/minio,aead/minio,hackintoshrao/minio,rushenn/minio,brendanashworth/minio,NitishT/minio,krishnasrinivas/minio,aead/minio,harshavardhana/minio,krisis/minio,harshavardhana/minio,harshavardhana/minio,harshavardhana/minio,mf-00/newgo,dutchcoders/minio,krishnasrinivas/minio-daily,krishnasrinivas/minio-daily,luomeiqin/minio,minio/minio,mf-00/newgo,NitishT/minio,NitishT/minio,krishnasrinivas/minio,dutchcoders/minio,harshavardhana/minio,minio/minio,abperiasamy/minio