Make filename in project properties copyable

(cherry-picked from d56ca40)

Author: nyalldawson

src/app/qgsprojectproperties.cpp

@@ -139,7 +139,7 @@ QgsProjectProperties::QgsProjectProperties( QgsMapCanvas* mapCanvas, QWidget *pa
   // Properties stored in QgsProject
 
   title( QgsProject::instance()->title() );
-  projectFileName->setText( QgsProject::instance()->fileName() );
+  mProjectFileLineEdit->setText( QgsProject::instance()->fileName() );
 
   // get the manner in which the number of decimal places in the mouse
   // position display is set (manual or automatic)