Logging tweaks in Cassandra's clearStorage()
Added new getKeys test method to KCVSTest
Reduce default surefire Xmx to 768m (was 1024m)
Modify new getKeys test for BDB compatibility

The current implementation of BerkeleyDBjeKeyColumnValueTest opens an
OrderedKCVS adapter with a fixed key length of 8 bytes.  Rather than
modify the BDB test config, I changed my recently-added getKeys test
to use 8-byte keys instead of 4-byte keys (as it did before this
commit).