Fix syntax of relative imports for Python3

In Python 3, relative imports must be written "from .module import name":
http://docs.python.org/3.0/whatsnew/3.0.html#removed-syntax

Change-Id: I2ec8a7330e63ea64d291f2f37f0c01cdf765d4f7
Remove eventlet related code in amqp driver

Because driver should rely on executor and not directly on eventlet,
delete eventlet related code. This also drop the old driver API.

This is the amqp part.

Change-Id: Ic6060058dafa4dabbc5e8c68bf231c818a7fec25
sysnchronize oslo-incubator modules

Update to get jsonutils compatible with Python 3.

The babel Python module is now required by gettextutils, and gettextutils is
imported by excutils.

Change-Id: Ifa6d6b29e2af58dfcfda1ab7efdb2f32cf9de655
Add Sample priority

With the routing notifier we can now issue high-frequency notifications
and not worry about clogging up the queue. The Sample priority will
be used for this situation.

Change-Id: Ia4aa77b7aa4ca9458e97ca3ed81101d92934b691
Merge "Add Sample priority"
Merge "Fix syntax of relative imports for Python3"
Merge "sysnchronize oslo-incubator modules"