Revert "WELD-1802 destroying conversation if an exception occurs when attaching bean store"

This reverts commit 311dd7916304b6275a4790bb77b8cccd6694c068.

The destruction of the conversation is not necessary. If an HTTP session times out all the conversations are destroyed automatically (in a seperate thread). Moreover the fix for WELD-1774 prevents from using leaked associated HTTP requests.
WELD-1802 Adding test to simulate the leaking scenario