Code changed in jenkins
User: Kohsuke Kawaguchi
Use DescribableList to handle the copy-on-write semantics correctly. The vector class just doesn't cut it, and we've been setting a new value to this field, which will violates all sorts of the concurrent programming practice.
This change has the nice side effect of removing class="vector" from the persisted XML. A test is added to make sure we can still read back such an XML.
(cherry picked from commit 7facc7733c7040536d4074a2c5805b75ee1d8f35)