[LyX/2.2.x] Fix DocBook DTD identifier for XML output.

[Richard Heck]

commit f7558646b1afb46c030037ea5ba9cbe37fbe605c
Author: Richard Heck <rgh...@lyx.org>
Date:   Sun Jan 8 13:37:00 2017 -0500

    Fix DocBook DTD identifier for XML output.
    
    Thanks to Martin Brown for the correct one.
    
    (cherry picked from commit b730419470061852e63ec0aaf5f2893605b03dde)
---
 src/Buffer.cpp |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/src/Buffer.cpp b/src/Buffer.cpp
index 2b2660e..94e94fa 100644
--- a/src/Buffer.cpp
+++ b/src/Buffer.cpp
@@ -2026,7 +2026,7 @@ void Buffer::writeDocBookSource(odocstream & os, string 
const & fname,
                if (! tclass.class_header().empty())
                        os << from_ascii(tclass.class_header());
                else if (runparams.flavor == OutputParams::XML)
-                       os << "PUBLIC \"-//OASIS//DTD DocBook XML//EN\" "
+                       os << "PUBLIC \"-//OASIS//DTD DocBook XML V4.2//EN\" "
                            << 
"\"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd\"";;
                else
                        os << " PUBLIC \"-//OASIS//DTD DocBook V4.2//EN\"";