Convention for merge changelogs

[Travis Vitek]

I've noticed that we aren't being consistent about the changelog text
for merged changes. Here are a few examples.

        http://svn.apache.org/viewvc?rev=617627&view=rev
        http://svn.apache.org/viewvc?rev=614790&view=rev
        http://svn.apache.org/viewvc?rev=612563&view=rev
        http://svn.apache.org/viewvc?rev=616004&view=rev

As you can see there isn't much consistency. Sometimes we copy the
date-user-email line from the original commit, simetimes we don't.
Sometimes we list the jira issue number on a line of its own. Is there
an expected or required format for the merge changelogs? 

Travis