@Override
    public FSDataOutputStream create(Path p) throws IOException {
      return new FaultyOutputStream(super.create(p), faultPos, fault);
    }
Faulty file system that will fail if you write past its fault position the FIRST TIME only;
thereafter it will succeed. Used by {@link TestHRegion} too.
hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestHStore.java