mgmt: Reinitialize multicast faces and partially reload config file on HUP signal

The following elements from the config file are reloaded:
- effective user/group
- log levels
- multicast faces (enable/disable)
- security

Change-Id: I6ddf124702b30610dd0404d8fbaa9a9d800f02bf
Refs: #1584
diff --git a/daemon/mgmt/command-validator.cpp b/daemon/mgmt/command-validator.cpp
index ea596b1..396cfe4 100644
--- a/daemon/mgmt/command-validator.cpp
+++ b/daemon/mgmt/command-validator.cpp
@@ -71,6 +71,8 @@
 
   const ConfigSection EMPTY_SECTION;
 
+  m_validator.reset();
+
   if (section.begin() == section.end())
     {
       throw ConfigFile::Error("No authorize sections found");