ruby.c: reduce RARRAY_PTR_USE region

* ruby.c (process_options): reduce RARRAY_PTR_USE region, make the
  path to be set before entering the region.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@47257 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* 2014-08-23

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@47258 b2dd03c8-39d4-4d8f-98ff-823fe69b080e