test-dns: note why we are calling deprecated functions in test
test-dns: note why we are calling deprecated functions in test

dns.isIP* are now net.isIP*. Note that we are testing to ensure they
work in the comments.

GabrielNicolasAvellaneda/luvit-upstream,AndrewTsao/luvit,sousoux/luvit,bsn069/luvit,GabrielNicolasAvellaneda/luvit-upstream,DBarney/luvit,zhaozg/luvit,boundary/luvit,DBarney/luvit,sousoux/luvit,rjeli/luvit,kaustavha/luvit,sousoux/luvit,kaustavha/luvit,rjeli/luvit,bsn069/luvit,boundary/luvit,rjeli/luvit,luvit/luvit,zhaozg/luvit,kaustavha/luvit,AndrewTsao/luvit,boundary/luvit,AndrewTsao/luvit,connectFree/lev,connectFree/lev,DBarney/luvit,boundary/luvit,DBarney/luvit,sousoux/luvit,boundary/luvit,bsn069/luvit,GabrielNicolasAvellaneda/luvit-upstream,rjeli/luvit,boundary/luvit,sousoux/luvit,sousoux/luvit,GabrielNicolasAvellaneda/luvit-upstream,luvit/luvit