Add spec for the new :flags keyword argument for File.open
Add spec for the new :flags keyword argument for File.open

* See #175.

ruby/spec,eregon/rubyspec,kachick/rubyspec,sgarciac/spec,ruby/spec,sgarciac/spec,sgarciac/spec,ruby/spec,nobu/rubyspec,nobu/rubyspec,kachick/rubyspec,ruby/rubyspec,ruby/rubyspec,eregon/rubyspec,kachick/rubyspec,eregon/rubyspec,nobu/rubyspec