Race condition when resolving identities in config subsystem

Config subsystem transforms identity QName to Class<?> object using LazyGeneratedCodecRegistry.

This codec registry however receives schema context from MD-SAL last. Config subsystem may have necessary schema and permits the config pusher to push config snapshot, but the codec registry does not see necessary yang modules.

In case of identities, the schema context is not necessary and the transformation can be performed without it. It just needs to get the name of the class from QName using utility code.