DERBY-6043: Make JQL default query mode for 'ant genrelnotes'

Made the switch to JQL, and cleaned up some ant code.
Note that you can still specify jira.filter.id explicitly if you wish to.

Patch file: derby-6043-1a-make_jql_default.diff


git-svn-id: https://svn.apache.org/repos/asf/db/derby/code/trunk@1434599 13f79535-47bb-0310-9956-ffa450edef68