[mruby] update how trailing `/` is handled
[mruby] update how trailing `/` is handled

Conflicts:
	lib/handler/mruby.c

mingodad/h2o,mingodad/h2o,mingodad/h2o,mingodad/h2o,mingodad/h2o,mingodad/h2o,mingodad/h2o,mingodad/h2o