HBASE-12219 Cache more efficiently getAll() and get() in FSTableDescriptors (addendum)

Signed-off-by: stack <stack@apache.org>
HBASE-8572 Enhance delete_snapshot.rb to call snapshot deletion API with regex

Signed-off-by: stack <stack@apache.org>
HBASE-12363 Improve how KEEP_DELETED_CELLS works with MIN_VERSIONS.