Set output_stream and error_stream to StringIO
Set output_stream and error_stream to StringIO

In RSpec 2.99, there's default formatters and it uses output_stream and
error_stream as reporting media. We have to protect output_stream
(stdout) from begin closed after examples finished.

jaymanklu/rrrspec,hirocaster/rrrspec,sauliusgrigaitis/rrrspec,cookpad/rrrspec,cookpad/rrrspec,sauliusgrigaitis/rrrspec,hirocaster/rrrspec,jaymanklu/rrrspec,jaymanklu/rrrspec,cookpad/rrrspec,hirocaster/rrrspec,sauliusgrigaitis/rrrspec