Remove some unused member variables

Change-Id: I4b1bcfe8da32bd48c601d1efdb7c3aac1d39cbce
Reviewed-by: Leandro Melo <leandro.melo@nokia.com>

src/libs/cplusplus/DeprecatedGenTemplateInstance.h

@@ -54,7 +54,6 @@ private:
     FullySpecifiedType gen(Symbol *symbol);
 
 private:
-    Symbol *_symbol;
     QSharedPointer<Control> _control;
     const Substitution _substitution;
 };