security: Add doxygen comments

Change-Id: Ieafe4d13513e626d84ef9e621694f69844785018
diff --git a/src/security/validator-regex.cpp b/src/security/validator-regex.cpp
index b85bad2..6569b58 100644
--- a/src/security/validator-regex.cpp
+++ b/src/security/validator-regex.cpp
@@ -17,8 +17,7 @@
 
 using namespace std;
 
-namespace ndn
-{
+namespace ndn {
 
 const shared_ptr<CertificateCache> ValidatorRegex::DefaultCertificateCache = shared_ptr<CertificateCache>();
 
@@ -62,7 +61,7 @@
     }
   else
     {
-      _LOG_DEBUG("Wrong Invalidity:");
+      _LOG_DEBUG("Wrong validity:");
       onValidationFailed(data);
       return;
     }
@@ -150,4 +149,4 @@
   return;
 }
 
-}//ndn
+} // namespace ndn