NOISSUE Add NullInstance for instances that can't be loaded

logic/InstanceList.cpp

@@ -37,6 +37,7 @@
 #include "minecraft/MinecraftVersion.h"
 #include "settings/INISettingsObject.h"
 #include "ftb/FTBPlugin.h"
+#include "NullInstance.h"
 
 const static int GROUP_FILE_FORMAT_VERSION = 1;
 
@@ -454,7 +455,7 @@ InstanceList::loadInstance(InstancePtr &inst, const QString &instDir)
 	}
 	else
 	{
-		return InstanceList::UnknownLoadError;
+		inst.reset(new NullInstance(m_globalSettings, instanceSettings, instDir));
 	}
 	inst->init();
 	return NoLoadError;