ISPN-4505 Lucene Directory polishing
ISPN-4505 Now using @Override for methods which couldn't be marked properly before
ISPN-4505 Document the fact we dropped compatibility with older Lucene versions
ISPN-4278 Add QOP support to the HotRod SASL implementation
ISPN-3743

Ignore some of the errors that can be thrown by a node while stopping:
IllegalStateException and NullPointerException.