[V2V] Expose virt-v2v-wrapper error message in options hash

[ghost]

When the disk conversion fails, the error message is really vague: Disk Transformation failed, so the user needs to look into the wrapper and virt-v2v logs to identify the cause. Since recently, virt-v2v-wrapper provides a human-readable error message based on virt-v2v log. An example is below

    {
      "started": true,
      "disks": [
        {
          "path": "[datastore13] tg-mini2/tg-mini2_3.vmdk",
          "progress": 100
        },
        {
          "path": "[datastore13] tg-mini2/tg-mini2_4.vmdk",
          "progress": 100
        }
      ],
      "pid": 30375,
      "disk_count": 2,
      "return_code": 0,
      "failed": true,
      "finished": true,
      "last_message": {
        "message": "Failed to create port",
        "type": "error"
      }
    }

This PR exposes the message from virt-v2v-wrapper in the task options hash, so that it can be consumed by Automate and the UI.

Associated RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=1595365

[ghost]

@miq-bot add_label transformation, enhancement, hammer/yes
@miq-bot add_reviewer @djberg96
@miq-bot add_reviewer @agrare

[miq-bot]

Checked commit fabiendupont@51f100f with ruby 2.3.3, rubocop 0.52.1, haml-lint 0.20.0, and yamllint 1.10.0
2 files checked, 0 offenses detected
Everything looks fine. ⭐

[djberg96]

Looks ok to me. :)

[simaishi]

Hammer backport details:

$ git log -1
commit aa22a823bf38b56b4c82fb8b0cac937016af6cb0
Author: Adam Grare <agrare@redhat.com>
Date:   Tue Mar 19 11:39:40 2019 +0100

    Merge pull request #18564 from fdupont-redhat/v2v_error_reporting_expose_virtv2v_message
    
    [V2V] Expose virt-v2v-wrapper error message in options hash
    
    (cherry picked from commit a617d3c7033e3b37e9153466efd75468918a827e)
    
    https://bugzilla.redhat.com/show_bug.cgi?id=1693747