`ipconfig /all`,got encoding error on non-english windows

`ipconfig /all` got an error: `invalid byte sequence in UTF-8`
when windows is non English Enviroment.

Fix it like this : http://stackoverflow.com/a/9420531/1355590

  encoding_options = {
    :invalid           => :replace,  # Replace invalid byte sequences
    :undef             => :replace,  # Replace anything not defined in ASCII
    :replace           => '',        # Use a blank for those replacements
    :universal_newline => true       # Always break lines with \n
  }
  non_ascii_string.encode(Encoding.find('ASCII'), encoding_options)