title: Spring jackson:date-format formatting changes after upgrade
body: <p>After upgrading from spring boot 1.2.6.RELEASE -> 1.3.1.RELEASE there seems to be a problem when using iso 8101 dateformat with timezone offset.
  In my application.yml the jackson date-format is set to format with timezone offset</p>
  
  <pre><code>spring:
     jackson:
        date-format: yyyy-MM-dd'T'HH:mm:ss.SSSXXX
  </code></pre>
  
  <p>With boot 1.2.6 this results in datetime formats with the correct iso 8601 timezone format like 2014-01-01T23:01:01.010+01:00</p>
  
  <p>But with boot 1.3.1 the format is kept in Zulu time zone
  2014-01-01T22:01:01.010Z</p>