MiniProjectTargetSelector: Make sure we always have a heading

Change-Id: I4ea5883e64bcae405ae00200616a1f915bdeffff
Reviewed-by: Eike Ziller <eike.ziller@theqtcompany.com>
Reviewed-by: Robert Loehning <robert.loehning@theqtcompany.com>

src/plugins/projectexplorer/miniprojecttargetselector.cpp

@@ -1490,7 +1490,7 @@ void MiniProjectTargetSelector::mousePressEvent(QMouseEvent *e)
 
 void MiniProjectTargetSelector::updateActionAndSummary()
 {
-    QString projectName;
+    QString projectName = QLatin1String(" ");
     QString fileName; // contains the path if projectName is not unique
     QString targetName;
     QString targetToolTipText;