WELD-1478 possible memory leak in HttpConversationContextImpl
Forgot to change serialVersionUID in previous commit
Fix SessionScopedProducerTest (mkouba pointed out that WebClient is not threadsafe)
Ignore exception thrown by requestDestroyed() when already handling another exception in requestInitialized()
WELD-1479 ConcurrentModificationException in CreationalContextImpl.destroyDependentInstance
WELD-1486 Remove Instance<ConversationContext> from AbstractConversationContext and ConversationImpl

Conflicts:
	impl/src/main/java/org/jboss/weld/context/AbstractConversationContext.java