C++: fixed source-to-project-part map calculation

When the information for a project is updated, the mapping was cleared
and only recalculated for the new project info. Thereby wiping out
the info for any previously added project.

Change-Id: Ic6999b9be07f8cb6b4638723e6c8c7d2d3ca52e7
Reviewed-by: Erik Verbruggen <erik.verbruggen@nokia.com>

src/plugins/cpptools/cppmodelmanager.cpp

@@ -934,11 +934,10 @@ void CppModelManager::updateProjectInfo(const ProjectInfo &pinfo)
 
     m_srcToProjectPart.clear();
 
-    foreach (const ProjectPart::Ptr &projectPart, pinfo.projectParts()) {
-        foreach (const QString &sourceFile, projectPart->sourceFiles) {
-            m_srcToProjectPart[sourceFile].append(projectPart);
-        }
-    }
+    foreach (const ProjectInfo &projectInfo, m_projects.values())
+        foreach (const ProjectPart::Ptr &projectPart, projectInfo.projectParts())
+            foreach (const QString &sourceFile, projectPart->sourceFiles)
+                m_srcToProjectPart[sourceFile].append(projectPart);
 }
 
 QList<CppModelManager::ProjectPart::Ptr> CppModelManager::projectPart(const QString &fileName) const