Adjust protocols/utils api

in deed, pipe parameters is unneed, because the nn_priolist_data or nn_dist_data struct will save pipe when we call nn_priolist_add(...)/nn_dist_add(...). 
to make the api better, i make this changes:
1. remove pipe param from nn_fq_xx() and nn_lb_xx() apis
2. remove pipe param from nn_dist_xx() apis