unix: clean up uv_tty_set_mode() a little
unix: clean up uv_tty_set_mode() a little

unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso