Adds support to negative on the contains operator

src/operators/contains.h

@@ -28,7 +28,8 @@ namespace operators {
 class Contains : public Operator {
  public:
     /** @ingroup ModSecurity_Operator */
-    Contains(std::string o, std::string p, bool i);
+    Contains(std::string op, std::string param, bool negation)
+        : Operator(op, param, negation) { }
     bool evaluate(Assay *assay, const std::string &exp) override;
 };