improve the resilience of some integration tests

Merge branch 'stable'

Merge pull request rabbitmq#154 from rabbitmq/rabbitmq-server-854

Test publisher confirms are not blocked by purge of durable queues

Merge pull request rabbitmq#154 from rabbitmq/rabbitmq-server-854

Test publisher confirms are not blocked by purge of durable queues

Merge pull request rabbitmq#154 from rabbitmq/rabbitmq-server-854

Test publisher confirms are not blocked by purge of durable queues

Merge pull request rabbitmq#154 from rabbitmq/rabbitmq-server-854

Test publisher confirms are not blocked by purge of durable queues

Delete resources before re-creating them here

Delete resources before re-creating them here

Merge branch 'stable'

Merge branch 'stable'