SLING-2877 : Regression: changes off SLING-2775 fail to set jcr:lastModified property on existing nodes. Apply patch from Tobias Bocanegra

git-svn-id: https://svn.apache.org/repos/asf/sling/trunk@1485588 13f79535-47bb-0310-9956-ffa450edef68
Use latest post servlet

git-svn-id: https://svn.apache.org/repos/asf/sling/trunk@1485589 13f79535-47bb-0310-9956-ffa450edef68