rabbit: more precise iterconsume timeout

The iterconsume always set the timeout of kombu to 1 second
even the requested timeout more precise or < 1 second.

This change fixes that.

Related bug: #1400268
Related bug: #1399257

Change-Id: I157dab80cdb4afcf9a5f26fa900f96f0696db502
qpid: honor iterconsume timeout

The qpid driver must always honor the timeout passed the iterconsume
method, this change fixes that.

Related bug: #1400268
Related bug: #1399257

Change-Id: I8f267fc8b5a7abc852f0caf84d1e7c2c342ba951
The executor doesn't need to set the timeout

It's up to the driver to set a suitable timeout for polling the broker,
this one can be different that the one requested by the driver
caller as long as the caller timeout is respected.

This change also adds a new driver listener API, to be able
to stop it cleanly, specially in case of timeout=None.

Closes bug: #1400268
Closes bug: #1399257
Change-Id: I674c0def1efb420c293897d49683593a0b10e291
Merge "rabbit: more precise iterconsume timeout"
Merge "qpid: honor iterconsume timeout"
Merge "The executor doesn't need to set the timeout"
Warns user if thread monkeypatch is not done

This change warns the user that it does have monkeypatched the
oslo.messaging library correclty.

Change-Id: Ice80ffc6cbc39919eac4bc0809992daea51b5922
Closes-bug: #1288878
Merge "Warns user if thread monkeypatch is not done"