cleanup_env (Irc::DBTree)

    # File lib/rbot/dbhash.rb, line 174
        def DBTree.cleanup_env()
          begin
            debug "DBTree: checking transactions ..."
            has_active_txn = @@env.txn_stat["st_nactive"] > 0
            if has_active_txn
              warning "DBTree: not all transactions completed!"
            end
            DBTree.cleanup_logs
            debug "DBTree: closing environment #{@@env}"
            path = @@env.home
            @@env.close
            @@env = nil
            if has_active_txn
              debug "DBTree: keeping file because of incomplete transactions"
            else
              debug "DBTree: cleaning up environment in #{path}"
              BDB::Env.remove("#{path}")
            end
          rescue Exception => e
            error "failed to clean up environment: #{e.pretty_inspect}"
          end
        end