Change-Id: I4440b3299e5a03652ecedb834992fc75de11b15b

stable/juno was just created for taskflow from the 0.6.1 tag so that we
can cap networkx (and other requirements) for taskflow in Juno.  This is
needed to unblock the gate-cinder-python26 job in Juno which uses
taskflow and with uncapped networkx, pulls in 1.10 which dropped py26
support.

As the first change to stable/juno for taskflow, this also updates
the .gitreview file.

Depends-On: I29aa97b542d82aabe770ad4431125ef5c67f6104

Closes-Bug: #1484267

Change-Id: Ie5fadc3f26b6897440023b2fdb47a07766061cbb

The code we had for adjusting the netutils urlsplit
function to add in a params method/property is no
longer needed as that functionality is now pushed into
the oslo.utils repo/package where it can be maintained
there in a more proper manner instead; so we can now
remove our adjustment code and just use the upstream
code instead.

Change-Id: I5ca05c0ac6a6221157a737ba20814cfd63adf51e

To enable a parallel process executor to be used without
having to pass in a futures executor allow for the executor
option to be a string 'processes' (or similar) that will cause
the default parallel process executor to be used automatically.

Also allow for a 'threads' string that ensure a parallel thread
executor is used to match the ability to uses processes.

This also adjusts the WBE engine to have a similar executor fetching
function (which in the WBE case now validates a provided executor to
be of the desired type).

Change-Id: I54a82584c32c697922507b4f6e01ea7b8acc73c6

To avoid consistency/threading/runtime issues stop the action
engine executor from being started if it is already running with
a valid worker thread.

Change-Id: I39925e55e7b171f289152d941ebdf390552f880c

Instead of having many queues (one per task) just have a shared
one and use sender identifiers to know which originating task
to proxy back to.

This scales better and avoids the needless polling of many
queues for a potential message to emit (and can now instead
just poll one queue); when now we can just poll a single
queue for any messages (this does though remove the ability to
throttle messages from a given sender).

Change-Id: I3566a5ab20ad15a80a4c6969f48b076ddde1d7ac