HBASE-2471's means you need to create region's folders for log splitting

[Jean-Daniel Cryans]

Hey guys,

Now that I committed HBASE-2471, new unit tests that play with log
splitting will need to create the region dirs _before_ using
HLogSplitter or it will refuse to do it. I've done the changes in
TestHLog, TestHLogSplit and TestWALReplay already.

Thx,

J-D