Log Message:
Add an explicit dependency on docbook-xsl>=1.67.0 rather than using whatever
other dependencies pull in:  earlier versions of docbook-xsl generate slightly
different html leading to a large number of unneccessary 'regen' commits in
htdocs.  Bump minor versions for this.

This is done during the freeze so as to ensure that it gets on the branch
and we can simply tell developers to install netbsd-www version 1.2.