remove the only section in the history appendix to workaround dblatex issue

dblatex generated LaTeX that failed with the "id" for link reference
in the sect1 when itr had no <title> to reference.
(A workaround is to set a <title>.)
But since this appendix only had one section
and looked off to have B1 with no title and no B2, just remove the
sect1 tags.
I added the id to the first <para> tag just in case someone uses
it to link.
Note I didn't reformat the content there.

I didn't get this reviewed as was trivial change.

doc/arm/Bv9ARM-book.xml

@@ -16922,8 +16922,7 @@ zone "example.com" {
 
     <appendix id="Bv9ARM.ch10">
       <title>A Brief History of the <acronym>DNS</acronym> and <acronym>BIND</acronym></title>
-      <sect1 id="historical_dns_information">
-	  <para>
+	  <para id="historical_dns_information">
 	    Although the "official" beginning of the Domain Name
 	    System occurred in 1984 with the publication of RFC 920, the
 	    core of the new system was described in 1983 in RFCs 882 and
@@ -17018,7 +17017,6 @@ zone "example.com" {
 	    of several corporations, and by the tireless work efforts of
 	    numerous individuals.
 	  </para>
-      </sect1>
     </appendix>
 
     <appendix id="Bv9ARM.ch11">