Update README.md to remove smart magic quote

On some versions of Chef and Ruby (particularly those current available on AWS Opsworks), the smart magic quote in the README.md can cause installation errors:

   /opt/aws/opsworks/local/lib/ruby/gems/2.0.0/gems/json-1.8.1/lib/json/common.rb:155:in `encode': "\xE2" on US-ASCII (Encoding::InvalidByteSequenceError)

This is an instance of the following bug: https://tickets.opscode.com/browse/COOK-522