blog.w.o to use own certificate, not wildcard

holmium was using our wildcard certificate to host the blog.  I've
changed it to use its own certificate, for reasons defined in the linked
RT ticket.  The change will also stop techblog.wikimedia.org from
rewriting via HTTPS, but that is depreciated from before the blogs were
merged years ago. I have left the http techblog vhost intact, as it
doesn't cost anything to do so at this time.

Change-Id: I33dff01e66af68796fbbadad8bd40a6f8a769b55
RT: 5010