Don't NPE when shutting down non-existent thrift server
Don't require the sysctl file to exist when deleting it
assume python is on path for windows for cqlsh.bat
patch by mstepura reviewed by dbrosius for cassandra-6145
add path to MmappedSegmentedFile assertions
Handle null correctly in CqlStorage
Patch by Alex Liu, reviewed by brandonwilliams for CASSANDRA-6180
Require logging in for Thrift CQL2/3 statement preparation

patch by Aleksey Yeschenko; reviewed by Sylvain Lebresne for
CASSANDRA-6254
Allow overriding max hin ttl.
Patch by Vishy Kasar, reviewed by brandonwilliams for CASSANDRA-5988
Show the root cause when failing to load a class
Patch by Jackson Chung, reviewed by brandonwilliams for CASSANDRA-6258