Complete delete backend regtests by checking deletion of a proxy with a
reference on an unnamed defaults instance. This operation is sensible as
the defaults refcount is decremented, and when the last backend is
removed, the defaults is also freed.
Add a reg-tests to test "del backend" CLI command. First, checks are
performed to ensure a backend cannot be deleted if not in the expected
state.
Then, a "del backend" success is tested. Stats are dumped to ensure the
backend instance is indeed removed.
Add a new regtests to validate backend creation at runtime. A server is
then added and requests made to validate the newly created instance
before (with force-be-switch) and after publishing.
Each frontend/backend/listen proxies is assigned an unique ID. It can
either be set explicitely via 'id' keyword, or automatically assigned on
post parsing depending on the available values.
It was expected that the first automatically assigned value would start
at '1'. However, due to a legacy bug this is not the case as this value
is always skipped. Thus, automatically assigned proxies always start at
'2' or more.
To avoid breaking the current existing state, this situation is now
acknowledged with the current patch. The code is rewritten with an
explicit warning to ensure that this won't be fixed without knowing the
current status. A new regtest also ensures this.
