Update GRANT/REVOKE test to cleanup all created objects during test cleanup

The tests now cleanup everything in the test cleanup routine. This fixes a flakiness
issue when loading from a snapshot. The problem was that one of the test table's HDFS
path contained old test data since the table wasn't dropped at the end of the test.

Change-Id: Idf50011b0b4ae69e724723c2cede94c9b45d0179
Reviewed-on: http://gerrit.sjc.cloudera.com:8080/4503
Reviewed-by: Lenni Kuff <lskuff@cloudera.com>
Tested-by: Lenni Kuff <lskuff@cloudera.com>