Removing rudimental n1 variable

There is no real need in n1, since it used in only at one place once.
Also it will prevent "variable ‘n1’ set but not used [-Werror=unused-but-set-variable]" error on build with -DLWS_MAX_SMP=N, where N > 1.

AG: also add LWS_MAP_SMP != 1 test to travis to catch this kind of thing sooner