Book: Fix XML validation failure reported by Axel Kollmorgen <axel@kollmorgen.net>.
Book: Fix XML validation failure reported
by Axel Kollmorgen <axel@kollmorgen.net>.

* doc/book/book.xml:
    Replace <subtitle><para>FOO</para><para>BAR</para></subtitle>
    with <subtitle>FOO</subtitle><subtitle>BAR</subtitle> .


git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@853178 13f79535-47bb-0310-9956-ffa450edef68

YueLinHo/Subversion,wbond/subversion,wbond/subversion,YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion