This jira adds the following 2 features to src/test
1) it extends DataNodeCluster to allow blocks to be injected for simulted data nodes.
2) a new command, CreatedEditsLog which creates an NN image edits logs that has a transactions for new files. The edits log file can be copied to the NN's image.
Using the two in conjunction one can inject a set of blocks in a NN and in a set of Datanodes and use it for testing, for example a cluster of 3K DNs
Improvement
Closed
Minor
Tools to inject blocks into name node and simulated data nodes for testing
