Remove unused method: ApplyRule::DiscardRules

fixes #12544

lib/config/applyrule.cpp

@@ -168,9 +168,3 @@ void ApplyRule::CheckMatches(void)
 		}
 	}
 }
-
-void ApplyRule::DiscardRules(void)
-{
-	m_Rules.clear();
-}
-

lib/config/applyrule.hpp

@@ -64,7 +64,6 @@ public:
 	static std::vector<String> GetTargetTypes(const String& sourceType);
 
 	static void CheckMatches(void);
-	static void DiscardRules(void);
 
 private:
 	String m_TargetType;