Dereference of an explicit null value

Defect 103443 (STATIC_C)
Checker FORWARD_NULL (subcategory deref_constant_null)
File: /src/mongo/db/storage/wiredtiger/wiredtiger_kv_engine.cpp
Function mongo::WiredTigerKVEngine::WiredTigerKVEngine(const std::_cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>> &, const std::cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>> &, mongo::ClockSource *, const std::_cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>> &, unsigned long, bool, bool, bool, bool)
/src/mongo/db/storage/wiredtiger/wiredtiger_kv_engine.cpp, line: 436
Dereferencing null pointer "this->_conn".

            invariantWTOK(_conn->query_timestamp(_conn, buf, "get=recovery"));