[LyX/master] Fix warning

[Jean-Marc Lasgouttes]

commit a9baa5380c4cdb42927800a17d3f95c2b8e75c54
Author: Jean-Marc Lasgouttes <lasgout...@lyx.org>
Date:   Tue Mar 31 17:08:04 2015 +0200

    Fix warning

diff --git a/src/frontends/qt4/InsetParamsWidget.cpp 
b/src/frontends/qt4/InsetParamsWidget.cpp
index 91e2e7b..86012a7 100644
--- a/src/frontends/qt4/InsetParamsWidget.cpp
+++ b/src/frontends/qt4/InsetParamsWidget.cpp
@@ -54,7 +54,7 @@ void InsetParamsWidget::addCheckedWidget(QLineEdit * input, 
QWidget * label)
 }
 
 
-bool InsetParamsWidget::checkWidgets(bool readonly) const
+bool InsetParamsWidget::checkWidgets(bool) const
 {
        bool valid = true;
        Q_FOREACH(CheckedWidget const & le, checked_widgets_)