Enhance exception throwing with Boost Exception library

Change-Id: I471023fc23ffaebe04d9668426b4c1b03e4962ba
Refs: #2997
diff --git a/src/security/sec-rule-relative.cpp b/src/security/sec-rule-relative.cpp
index 042d04f..4bf5eb9 100644
--- a/src/security/sec-rule-relative.cpp
+++ b/src/security/sec-rule-relative.cpp
@@ -46,7 +46,7 @@
     m_signerNameRegex(signerRegex, signerExpand)
 {
   if (op != ">" && op != ">=" && op != "==")
-    throw Error("op is wrong!");
+    BOOST_THROW_EXCEPTION(Error("op is wrong"));
 }
 
 SecRuleRelative::~SecRuleRelative()