Description of problem:
-----------------------
If minor update of RHOS-11 is cancelled there is no easy way to restart the update.
Initially reported in bz 1434437.

Copying comment3 from bz 1434437:
---------------------------------

Steps to continue an update:

1. openstack stack resource list -n 5 -f yaml --filter name=UpdateDeployment overcloud

This command will give you the resource that the hook is on. You will get output similar to this:

- physical_resource_id: 50da754b-2e09-45ff-8836-6a8b097337b6
  resource_name: UpdateDeployment
  resource_status: UPDATE_COMPLETE
  resource_type: OS::Heat::SoftwareDeployment
  stack_name: overcloud-Controller-cnu5246du7ej-0-qcu5iunuiqmm
  updated_time: '2017-03-22T12:53:27Z'
- physical_resource_id: 24718cee-63fb-4620-955a-20fca5678316
  resource_name: UpdateDeployment
  resource_status: UPDATE_COMPLETE
  resource_type: OS::Heat::SoftwareDeployment
  stack_name: overcloud-Compute-mwb5lla6twbn-0-tuysaeiyisoi
  updated_time: '2017-03-22T12:58:04Z'

2. openstack stack event list --resource UpdateDeployment overcloud-Controller-cnu5246du7ej-0-qcu5iunuiqmm
openstack stack event list --resource UpdateDeployment overcloud-Compute-mwb5lla6twbn-0-tuysaeiyisoi

The last few lines of the output from these commands (you will run this for every UpdateDeployment resource) will look similar to this:

2017-03-22 12:32:31Z [UpdateDeployment]: UPDATE_COMPLETE  UPDATE paused until Hook pre-update is cleared

If you see that, then you know the breakpoint has been reached, and needs to be cleared.

3. openstack stack hook clear overcloud-Controller-cnu5246du7ej-0-qcu5iunuiqmm UpdateDeployment

This, as you can guess, will clear the breakpoint and allow the update to continue. If you run the event list again, you will see:

2017-03-22 12:53:27Z [UpdateDeployment]: UPDATE_COMPLETE  Hook pre-update is cleared
2017-03-22 12:53:27Z [UpdateDeployment]: UPDATE_IN_PROGRESS  state changed
2017-03-22 12:54:21Z [UpdateDeployment]: SIGNAL_IN_PROGRESS  Signal: deployment 50da754b-2e09-45ff-8836-6a8b097337b6 succeeded
2017-03-22 12:54:22Z [UpdateDeployment]: UPDATE_COMPLETE  state changed

4. openstack stack list

    Monitor the stack for completion.

@Brad - if U have other ideas - please add them here.