Fix module event prioritization which was broken with the newer

auto-attach event stuff.

Also remove logically dead code from os_defcon, and make os_defcon akill
similar masks to os_session when enforcing session akills.

Fixes #1618 which relies on os_session to be prioritized before
os_defcon.

modules/protocol/unreal.cpp

@@ -1258,7 +1258,10 @@ class ProtoUnreal : public Module
 	{
 
 		this->AddModes();
+	}
 
+	void Prioritize() anope_override
+	{
 		ModuleManager::SetPriority(this, PRIORITY_FIRST);
 	}