HPX_LIMIT does not work for local dataflow

[mariomulansky]

Despite the recent fix, it is still impossible to use functors with more than 6 arguments in local dataflow objects. Adding the following code to hpx/tests/regressions/lcos/regression_set_hpx_limit_771.cpp results in compile errors:

future< double > f = make_ready_future( 1.0 );
f = hpx::lcos::local::dataflow( hpx::launch::sync , 
                               unwrapped( [](double x1 , double x2 , double x3 , double x4 ,
                                         double x5 , double x6 , double x7 ) -> double 
                                         { return x1; } ) , 
                               f , f , f , f , f , f , f );