Adjust my prior change to better utilize structured form submission to accomodate a plugins that are not using p:config-assignedLabel
mark the legacy jelly endpoints as DoNotUse
[maven-release-plugin] prepare release jenkins-1.588
[maven-release-plugin] prepare for next development iteration
updated changelog for release
Merge pull request #1447 from mattmoor/labels

Adjust my prior change to better utilize structured form submission...
updated changelog as a part of the release
merged back the RC branch