Bug #26021 - ndb: valgrind warning handle_trailing_share/ndbcluster_free_share invalid read

sql/ha_ndbcluster.cc:
  Bug #26021: make sure ndbcluster_create_event_ops even if no binlogging as flags NSF_NO_BINLOG is set there
  set NSS_DROPPED state in handle_trailing_share if appropriate
  added dbug printout and comments for NDB_SHARE references
sql/ha_ndbcluster_binlog.cc:
  Bug #26021: set NSF_NO_BINLOG if !ndb_binlog_running
  Bug #26021: only reuse share if share_may_exist
  setup apply_status table to be logged always, even if no binlogging
  added dbug printout and comments for NDB_SHARE references