Enhance ENABLE_COMPRESSION to include sparse files

[SysEngDan]

Enhancement: Add the S argument to tar when ENABLE_COMPRESSION is enabled to save space on VMDK files.

Background: If you create a 500GB thin provisioned disk and place only 5GB of actual data in it, then running ls -lhs shows that the .vmdk file is 500GB but only used 5GB of space on the disk. If you create a tar archive without S, the size of the .tar file is 500GB, however if you include S, the resulting .tar will be 5GB.