Debugger: Update internal buffer before checking dirtyness

Fixes: QTCREATORBUG-29746
Change-Id: I63f3c5bd2c628b42ba23dd19d80a410dbca8cfc1
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/plugins/debugger/debuggersourcepathmappingwidget.cpp

@@ -461,6 +461,12 @@ void SourcePathMapAspect::toMap(Store &) const
     QTC_CHECK(false);
 }
 
+bool SourcePathMapAspect::isDirty()
+{
+    guiToBuffer();
+    return m_internal != m_buffer;
+}
+
 void SourcePathMapAspect::addToLayout(Layouting::LayoutItem &parent)
 {
     QTC_CHECK(!d->m_widget);