Can we tighten this up a bit?  Instead of
```scala
val rddInfo = sc.persistentRdds.get(rddId) match {...}
rddInfo
```
just
```scala
sc.persistentRdds.get(rddId).map {r =>
  val rddName = Option(r.name).getOrElse(rddKey)
  val rddStorageLevel = r.getStorageLevel
  RDDInfo(rddId, rddName, rddStorageLevel, rddBlocks.length, r.partitions.size, memSize, diskSize)
  }
```