Catch errors when the JVM pulls the rug out from GCInspector
patch by Josh McKenzie; reviewed by jbellis for CASSANDRA-5345
merge from 2.0
merge
update changes
Merge branch 'cassandra-2.1.0' into cassandra-2.1

Conflicts:
	CHANGES.txt
remove errant code block
Give read access to system.schema_usertypes to all authenticated users

patch by Mike Adamson; reviewed by Aleksey Yeschenko for CASSANDRA-7578

Conflicts:
	CHANGES.txt
Fix ReversedType(DateType) mapping to native protocol

patch by Karl Rieb; reviewed by Aleksey Yeschenko for CASSANDRA-7576

Conflicts:
	CHANGES.txt
Fix native protocol drop user type notification

patch by Aleksey Yeschenko; reviewed by Tyler Hobbs for CASSANDRA-7571

Conflicts:
	CHANGES.txt
Merge branch 'cassandra-2.1.0' into cassandra-2.1
Fix errors when dropping non-existent indexes

Patch by Robert Stupp; review by Tyler Hobbs for CASSANDRA-7590
Merge branch 'cassandra-2.1.0' into cassandra-2.1
Always merge ranges owned by a single node in DES

Patch by Ala' Alkhaldi; review by Tyler Hobbs for CASSANDRA-6930
Merge branch 'cassandra-2.0' into cassandra-2.1.0

Conflicts:
	CHANGES.txt
Merge branch 'cassandra-2.1.0' into cassandra-2.1
Add cqlsh completion for IF [NOT] EXISTS in CREATE/DROP USER

Patch by Michał Michalski; review by Tyler Hobbs for CASSANDRA-7611
Merge branch 'cassandra-2.0' into cassandra-2.1.0

Conflicts:
	CHANGES.txt
Merge branch 'cassandra-2.1.0' into cassandra-2.1
Add cqlsh completion for IF [NOT] EXISTS in CREATE/DROP USER

Patch by Michał Michalski; review by Tyler Hobbs for CASSANDRA-7611

Conflicts:
	CHANGES.txt
Fix sstablelevelresetter hang

patch by yukim; reviewed by krummas for CASSANDRA-7614