Incorrect RKS size check

[nsoblath]

In daq_control::handle_run_command_request(), the minimum size of the RKS is currently 2, when it should be 3.

Lines 802ff

        if( a_request->parsed_rks().size() < 2 )
        {
            return a_reply_pkg.send_reply( dripline::retcode_t::message_error_invalid_key, "RKS is improperly formatted: [queue].run-command.[stream].[node].[command]" );
        }

But, as is noted on line 804, the desired RK is: [queue].run-command.[stream].[node].[command], so it requires at least 3 arguments.

Additional thing to fix: the returned error message contains a mistake: the name of the command is run-daq-cmd, not run-command.