Full support of multiple hosts in transport url

This patch add the support of multiple hosts in transport url for rabbit and
qpid drivers. And also fix the amqp connection pool management to allow
to have one pool by transport.

Implements blueprint multiple-hosts-support-in-url

Co-Authored-By: Ala Rezmerita <ala.rezmerita@cloudwatt.com>
Change-Id: I5aff24d292b67a7b65e33e7083e245efbbe82024
Fix typo in docstring of notify/notifier

Change-Id: Idd9f60e4d7ba65157f82f2a4c128f63c3ad6e805
Updated from global requirements

Change-Id: Iccddbe52b2550f81189f23c9f5624def817681ad
Remove dependent module py3kcompat

Module py3kcompat was removed from oslo-incubator, we can use
six directly.

Syncing module network_utils:
162e850 Remove import workaround of SplitResult
897aa7c urlsplit issues with IPv6 addresses in python26
35dc1d7 py3kcompat: remove

Change-Id: I71446362209c306c7e8858f4713a59b84fbcc1b2
Closes-Bug: #1280033
Merge "Updated from global requirements"
Remove str() from LOG.* and exceptions

gettextutils is expecting to receive unicode strings
rather than basestrings. A basestring can cause an
unhandled exception in the logging code. To help avoid
such issues we should remove str() from LOG.* messages and
exceptions. We have verified that the %s formatting code
properly handle getting strings to unicode where necessary.

Copied from https://review.openstack.org/#/c/77722

Change-Id: I082af5c9ae8bf9859382c2c387b10b48358e10b3
Related-Bug: #1286306
Synced jsonutils from oslo-incubator

The sync includes change that drastically enhances performance on Python
2.6 with fresh simplejson library installed.

The latest commit in oslo-incubator:
- 732bdb6297eb9de81667f7713ebcb1ccc2ee45a7

Change-Id: Ib3dc0b713ed90396919feba018772243b3b9c90f
Closes-Bug: 1314129
Merge "Synced jsonutils from oslo-incubator"
Updated from global requirements

Change-Id: Ie783701512f121acf9360ea8025e9996c67f41fb
Fix passing envelope variable as timeout

The envelope variable is being passed positionally in the timeout spot.

Change-Id: I64defdb0a9544d8c2ae69b38f723937b324ae504
Merge "Remove dependent module py3kcompat"
Merge "Fix passing envelope variable as timeout"
Merge "Full support of multiple hosts in transport url"