Adds new method for rule merge

IMPORTANT: SecDefaultAction specified on a child configuration will
overwrite the ones specified on the parent; Previously it was
concatenating.

src/actions/rev.cc

@@ -34,7 +34,6 @@ bool Rev::init(std::string *error) {
 
 
 bool Rev::evaluate(RuleWithActions *rule, Transaction *transaction) {
-    rule->m_rev = m_rev;
     return true;
 }