security: Enable load of ValidatorConf from a boost::property_tree section

The functionality was already there, but was marked private.
This commit makes this function a public interface of ValidatorConf.

Change-Id: I5de598bc43949685963bff979959775733c3a639
diff --git a/src/security/validator-config.cpp b/src/security/validator-config.cpp
index 2085daf..3617772 100644
--- a/src/security/validator-config.cpp
+++ b/src/security/validator-config.cpp
@@ -70,12 +70,12 @@
       throw security::conf::Error(msg.str());
     }
 
-  process(tree, filename);
+  load(tree, filename);
 }
 
 void
-ValidatorConfig::process(const security::conf::ConfigSection& configSection,
-                         const std::string& filename)
+ValidatorConfig::load(const security::conf::ConfigSection& configSection,
+                      const std::string& filename)
 {
   BOOST_ASSERT(!filename.empty());