io.c: common oflags

* io.c (copy_stream_body): move common open flags.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42708 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
io.c: copy in binary mode

* io.c (copy_stream_body): should write in binary mode.  based on a
  patch by godfat (Lin Jen-Shin) at [ruby-core:56556].
  [ruby-core:56518] [Bug #8767]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42709 b2dd03c8-39d4-4d8f-98ff-823fe69b080e