struct.c: no rb_class_real twice

* struct.c (inspect_struct): as rb_obj_class() returns real class
  name, so rb_class_name is not needed.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@47238 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
compar.c: use Module#to_s

* compar.c (rb_cmperr): use Module#to_s so that names in a message
  can be overridden by to_s.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@47239 b2dd03c8-39d4-4d8f-98ff-823fe69b080e