[DefaultContext] ContextFactoryInterface aliases not updated when using defaultContext.id config

[alexandre-abrioux]

Hi,

It looks like the creation of aliases to enable autowiring in 9f395cb introduced a issue.

When an app service is dependent of either SerializationContextFactoryInterface or DeserializationContextFactoryInterface and the app is using the according default_context.serialization.id or default_context.deserialization.id configuration option, the following ServiceNotFoundException exception triggers:

You have requested a non-existent service "jms_serializer.configured_serialization_context_factory".

This issue comes from the fact that when using the default_context.serialization.id option the jms_serializer.serialization_context_factory service alias is changed from the jms_serializer.configured_serialization_context_factory service to the service declared in the option, while the JMS\Serializer\ContextFactory\SerializationContextFactoryInterface service that got introduced in 9f395cb stays inchanged and still points to the jms_serializer.configured_serialization_context_factory service (a service that gets removed afterward):

JMSSerializerBundle/DependencyInjection/JMSSerializerExtension.php

Lines 166 to 170 in 5793ec5

	if (isset($config['default_context'][$configKey]['id'])) {
	$container->setAlias('jms_serializer.' . $configKey . '_context_factory', new Alias($config['default_context'][$configKey]['id'], true));
	$container->removeDefinition($serviceId);
	continue;
	}

I created a test case that supports my claim (instructions in README):
https://github.com/alexandre-abrioux/JMSSerializerBundle-testDefaultContextID

Following the creation of this issue I will submit a pull request to try and fix it.

Thank you!