Include extensions/ and xsl-java/ changes in ChangeLog.xml and

Include extensions/ and xsl-java/ changes in ChangeLog.xml and
NEWS* file output for now (though those directories are now
removed, there were changes in them between the 1.72.0 release and
now, so we want to get those into the docbook-xsl NEWS* file
output for the 1.73.2 release (which like the 1.73.1 release, will
ship with NEWS* files that list all the changes since the last
major release, 1.72.0 in this case. For 1.74.0 and after, we'll
drop the extensions/ and xsl-java/ dirs from changelog/NEWS output
(because they now really are gone, so there won't be any more
changes being made to them...)