* unit-tests: Unit tests for erasureCreateFile and erasureReadFile.
* appendFile() should return errXLWriteQuorum.
* TestErasureReadFileOffsetLength() tests erasureReadFile() for different offset and lengths.
* Fix for the failure seen in the erasure read unit test case. Issue #2227
* Move common erasure setup code to newErasureTestSetup()
* Review fixes. Add few more test cases for erasureReadFile.