[LyX/master] Use default btprint value in the UI if none is given.

[Juergen Spitzmueller]

commit ed1b67b7ca69b1fd7d9214810d14b0525d44eb6a
Author: Juergen Spitzmueller <sp...@lyx.org>
Date:   Sun Sep 10 10:51:42 2017 +0200

    Use default btprint value in the UI if none is given.
---
 src/frontends/qt4/GuiBibtex.cpp |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/src/frontends/qt4/GuiBibtex.cpp b/src/frontends/qt4/GuiBibtex.cpp
index 1f87b6a..45ad6ca 100644
--- a/src/frontends/qt4/GuiBibtex.cpp
+++ b/src/frontends/qt4/GuiBibtex.cpp
@@ -338,7 +338,11 @@ void GuiBibtex::updateContents()
        if (usingBiblatex() && !buffer().masterParams().multibib.empty())
                btPrintCO->addItem(qt_("all reference units"), 
toqstr("bibbysection"));
 
-       
btPrintCO->setCurrentIndex(btPrintCO->findData(toqstr(params_["btprint"])));
+       docstring btprint = params_["btprint"];
+       if (btprint.empty())
+               // default
+               btprint = from_ascii("btPrintCited");
+       btPrintCO->setCurrentIndex(btPrintCO->findData(toqstr(btprint)));
 
        // Only useful for biblatex
        biblatexOptsLA->setVisible(biblatex);