Accept all thrift update on CQL3 cf but don't expose their metadata

patch by slebresne; reviewed by xedin for CASSANDRA-4377

Conflicts:
	CHANGES.txt
cqlsh: use system.schema_columnfamilies to fetch cf names in CQL3 mode
Fix version in CHANGES.txt
Merge branch 'dse-3.0' into DSP-1313

Conflicts:
	CHANGES.txt
Merge pull request #14 from riptano/DSP-1313

Dsp 1313