Vaadin views keeping connection open as long as the view has not exited
For Views using the AbstractPresenter a conversation is started when the view is initialized and is closed when the view exits.
These caused open connections to accumulate. For each opened view a connection is kept open until the suer explicitly exist the view. If the browser window showing the view is closed the view if not being notifies and will not exit the used connection is thus kept open and will never? close. The connection pool which is limited to max 15 connections is running out of connections quite soon due to this probelm.
Revert "enabling transaction close on conversation unbind after ref #6780 is fixed this could also have en effect to ref #7035"
need to revert due to problems with transaction synchronization being not active
This reverts commit ec18134aae9b2699aebfcf378da03d767332dcb7.