YARN-4293 has broken Slider's build, MockNodeReport needs a new field.
The datatype returned in the getter dates from
YARN-1012; it's in Hadoop 2.8+ only. This means that we'd need to switch to 2.8 only...not likely for a while.
Otherwise, improve that mocking somehow, without going near the new method. Maybe, just maybe, groovy will let us get away with that