Fix potential deadlock in the native protocol

patch by slebresne; reviewed by jbellis for CASSANDRA-5926
Merge branch 'cassandra-1.2' into cassandra-2.0.0
Fix typo
Remove deprecated native_transport_min_threads option
Merge branch 'cassandra-2.0.0' into cassandra-2.0
Fix dateOf() function for pre-2.0 timestamp columns

patch by Aleksey Yeschenko; reviewed by Sylvain Lebresne for
CASSANDRA-5928
Merge branch 'cassandra-2.0.0' into cassandra-2.0