[V2V] Don't use the ssh agent when verifying credentials

[djberg96]

When verifying credentials for V2V we should not attempt to use the ssh-agent because, in practice, it isn't running on the hosts we connect to.

At the moment the net-ssh library sets the :use_agent option to true by default: https://www.rubydoc.info/github/net-ssh/net-ssh/Net/SSH. While this does not prevent the verification from working, it does generate some potentially misleading log information:

net.ssh.authentication.agent[a90031c]: Q-task_id([job_dispatcher]) could not connect to ssh-agent: Agent not configured

Fixes https://bugzilla.redhat.com/show_bug.cgi?id=1724487

[djberg96]

@miq-bot add_labels transformation, changelog/yes, hammer/no

[djberg96]

@miq-bot add_reviewer @agrare

[ghost]

@miq-bot remove-label hammer/no
@miq-bot add-label hammer/yes

@djberg96 @agrare I'm changing the labels to get it backported in Hammer. The change is pretty small, so the risk is minimal.

[simaishi]

Hammer backport details:

$ git log -1
commit f3fd05137e83b7a4c80f2d8b1850060b8d990001
Author: Adam Grare <agrare@redhat.com>
Date:   Fri Jun 28 14:46:57 2019 -0400

    Merge pull request #18920 from djberg96/conversion_host_use_agent
    
    [V2V] Don't use the ssh agent when verifying credentials
    
    (cherry picked from commit 049727a5f6369a624dc8f1ebd115effcd927ef76)
    
    Fixes https://bugzilla.redhat.com/show_bug.cgi?id=1725960