Update to 2.0.6 (DATASET-949).
 * Avoid race-prone second "scrub" of system keyspace (CASSANDRA-6797)
 * Pool CqlRecordWriter clients by inetaddress rather than Range
   (CASSANDRA-6665)
 * Fix compaction_history timestamps (CASSANDRA-6784)
 * Compare scores of full replica ordering in DES (CASSANDRA-6883)
 * fix CME in SessionInfo updateProgress affecting netstats (CASSANDRA-6577)
 * Allow repairing between specific replicas (CASSANDRA-6440)
 * Allow per-dc enabling of hints (CASSANDRA-6157)
 * Add compatibility for Hadoop 0.2.x (CASSANDRA-5201)
 * Fix EstimatedHistogram races (CASSANDRA-6682)
 * Failure detector correctly converts initial value to nanos (CASSANDRA-6658)
 * Add nodetool taketoken to relocate vnodes (CASSANDRA-4445)
 * Fix upgradesstables NPE for non-CF-based indexes (CASSANDRA-6645)
 * Improve nodetool cfhistograms formatting (CASSANDRA-6360)
 * Expose bulk loading progress over JMX (CASSANDRA-4757)
 * Correctly handle null with IF conditions and TTL (CASSANDRA-6623)
 * Account for range/row tombstones in tombstone drop
   time histogram (CASSANDRA-6522)
 * Stop CommitLogSegment.close() from calling sync() (CASSANDRA-6652)
 * Make commitlog failure handling configurable (CASSANDRA-6364)
 * Avoid overlaps in LCS (CASSANDRA-6688)
 * Improve support for paginating over composites (CASSANDRA-4851)
 * Fix count(*) queries in a mixed cluster (CASSANDRA-6707)
 * Improve repair tasks(snapshot, differencing) concurrency (CASSANDRA-6566)
 * Fix replaying pre-2.0 commit logs (CASSANDRA-6714)
 * Add static columns to CQL3 (CASSANDRA-6561)
 * Optimize single partition batch statements (CASSANDRA-6737)
 * Disallow post-query re-ordering when paging (CASSANDRA-6722)
 * Fix potential paging bug with deleted columns (CASSANDRA-6748)
 * Fix NPE on BulkLoader caused by losing StreamEvent (CASSANDRA-6636)
 * Fix truncating compression metadata (CASSANDRA-6791)
 * Fix UPDATE updating PRIMARY KEY columns implicitly (CASSANDRA-6782)
 * Fix IllegalArgumentException when updating from 1.2 with SuperColumns
   (CASSANDRA-6733)
 * FBUtilities.singleton() should use the CF comparator (CASSANDRA-6778)
 * Fix CQLSStableWriter.addRow(Map<String, Object>) (CASSANDRA-6526)
 * Fix HSHA server introducing corrupt data (CASSANDRA-6285)
 * Fix CAS conditions for COMPACT STORAGE tables (CASSANDRA-6813)
Merged from 1.2:
 * Add CMSClassUnloadingEnabled JVM option (CASSANDRA-6541)
 * Catch memtable flush exceptions during shutdown (CASSANDRA-6735)
 * Fix broken streams when replacing with same IP (CASSANDRA-6622)
 * Fix upgradesstables NPE for non-CF-based indexes (CASSANDRA-6645)
 * Fix partition and range deletes not triggering flush (CASSANDRA-6655)
 * Fix mean cells and mean row size per sstable calculations (CASSANDRA-6667)
 * Compact hints after partial replay to clean out tombstones (CASSANDRA-6666)
 * Log USING TTL/TIMESTAMP in a counter update warning (CASSANDRA-6649)
 * Don't exchange schema between nodes with different versions (CASSANDRA-6695)
 * Use real node messaging versions for schema exchange decisions (CASSANDRA-6700)
 * IN on the last clustering columns + ORDER BY DESC yield no results (CASSANDRA-6701)
 * Fix SecondaryIndexManager#deleteFromIndexes() (CASSANDRA-6711)
 * Fix snapshot repair not snapshotting coordinator itself (CASSANDRA-6713)
 * Support negative timestamps for CQL3 dates in query string (CASSANDRA-6718)
 * Avoid NPEs when receiving table changes for an unknown keyspace (CASSANDRA-5631)
 * Fix bootstrapping when there is no schema (CASSANDRA-6685)