Fix #119 - adjust du output parser to HADOOP-6857

HADOOP-6857 introduced another column (spaceConsumed) in du output.
Since snakebite still outputs only size (length), and path for now we
ignore spaceConsumed - this should change in #120.
Merge pull request #121 from spotify/rav/fix_minicluster_du_parser

Fix #119 - adjust du output parser to HADOOP-6857