Log Message:
Update py-cassandra-driver to 2.5.0

2.5.0
- Integrated cqlengine object mapping package
- Utility functions for converting timeuuids and datetime (PYTHON-99)
- Schema metadata fetch window randomized, config options added (PYTHON-202)
- Support for new Date and Time Cassandra types (PYTHON-190)
- Fix index target for collection indexes (full(), keys()) (PYTHON-222)
- Thread exception during GIL cleanup (PYTHON-229)
- Workaround for rounding anomaly in datetime.utcfromtime (Python 3.4)
  (PYTHON-230)
- Normalize text serialization for lookup in OrderedMap (PYTHON-231)
- Support reading CompositeType data (PYTHON-234)
- Preserve float precision in CQL encoding (PYTHON-243)

2.1.4
- SaslAuthenticator for Kerberos support (PYTHON-109)
- Heartbeat for network device keepalive and detecting failures on idle
  connections (PYTHON-197)
- Support nested, frozen collections for Cassandra 2.1.3+ (PYTHON-186)
- Schema agreement wait bypass config, new call for synchronous schema
  refresh (PYTHON-205)
- Add eventlet connection support (PYTHON-194)
- Schema meta fix for complex thrift tables (PYTHON-191)
- Support for 'unknown' replica placement strategies in schema meta
  (PYTHON-192)
- Resolve stream ID leak on set_keyspace (PYTHON-195)
- Remove implicit timestamp scaling on serialization of numeric
  timestamps (PYTHON-204)
- Resolve stream id collision when using SASL auth (PYTHON-210)
- Correct unhexlify usage for user defined type meta in Python3 (PYTHON-208)