Fix small leak on exit.

I am not even sure we should do that.

src/plugins/debugger/breakhandler.cpp

@@ -231,6 +231,11 @@ BreakHandler::BreakHandler(QObject *parent)
 {
 }
 
+BreakHandler::~BreakHandler()
+{
+    clear();
+}
+
 int BreakHandler::columnCount(const QModelIndex &parent) const
 {
     return parent.isValid() ? 0 : 6;

src/plugins/debugger/breakhandler.h

@@ -113,6 +113,7 @@ class BreakHandler : public QAbstractItemModel
 
 public:
     explicit BreakHandler(QObject *parent = 0);
+    ~BreakHandler();
 
     void removeAllBreakpoints();
     void setAllPending();