CompilationDatabase: Remove unnneded ::fromMap() reimplementaion

Change-Id: I2e9440f146b8ba485d3080e74927a05ae7d68824
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/plugins/compilationdatabaseprojectmanager/compilationdatabaseproject.h

@@ -62,7 +62,6 @@ public:
     ProjectExplorer::Kit *kit() const { return m_kit.get(); }
 
 private:
-    RestoreResult fromMap(const QVariantMap &map, QString *errorMessage) override;
     std::unique_ptr<ProjectExplorer::Kit> m_kit;
 };