Description of problem:
When we configure a hook using the default image to execute the hooks, CMT cannot execute the hooks and the migration is stuck forever.


Version-Release number of selected component (if applicable):
CMT 1.3
SOURCE CLUSTER: azure OCP 4.2
TARGET CLUSTER: azure OCP 4.5

How reproducible:
Always

Steps to Reproduce:
1. Create a namespace
   oc new-project bztest

2. Create a migration plan for this namespace

3. Add a hook for this migration (no matter which hook, or which playbook). Use the default "Ansible runtime image".

4. Run the migration


Actual results:
In the namespace used to run the hook, we find that the pods

$ oc get pods
NAME                          READY   STATUS                 RESTARTS   AGE
hooks-prebackup-54mpd-pkx7f   0/1     CreateContainerError   0          37m
hooks-prebackup-54mpd-rr4qh   0/1     CreateContainerError   0          7m42s

Looking the those pods' logs we find this messages

  Warning  Failed  35m  kubelet, cam-src-8320-v2ksq-worker-northcentralus-67q7l  Error: container create failed: time="2020-09-14T12:05:45Z" level=error msg="container_linux.go:349: starting container process caused \"exec: \\\"/bin/entrypoint\\\": stat /bin/entrypoint: no such file or directory\""
container_linux.go:349: starting container process caused "exec: \"/bin/entrypoint\": stat /bin/entrypoint: no such file or directory"
  Warning  Failed  35m  kubelet, cam-src-8320-v2ksq-worker-northcentralus-67q7l  Error: container create failed: time="2020-09-14T12:05:58Z" level=error msg="container_linux.go:349: starting container process caused \"exec: \\\"/bin/entrypoint\\\": stat /bin/entrypoint: no such file or directory\""
container_linux.go:349: starting container process caused "exec: \"/bin/entrypoint\": stat /bin/entrypoint: no such file or directory"
  Warning  Failed  34m  kubelet, cam-src-8320-v2ksq-worker-northcentralus-67q7l  Error: container create failed: time="2020-09-14T12:06:10Z" level=error msg="container_linux.go:349: starting container process caused \"exec: \\\"/bin/entrypoint\\\": stat /bin/entrypoint: no such file or directory\""
container_linux.go:349: starting container process caused "exec: \"/bin/entrypoint\": stat /bin/entrypoint: no such file or directory"
  Warning  Failed  34m (x3 over 34m)  kubelet, cam-src-8320-v2ksq-worker-northcentralus-67q7l  (combined from similar events): Error: container create failed: time="2020-09-14T12:06:54Z" level=error msg="container_linux.go:349: starting container process caused \"exec: \\\"/bin/entrypoint\\\": stat /bin/entrypoint: no such file or directory\""
container_linux.go:349: starting container process caused "exec: \"/bin/entrypoint\": stat /bin/entrypoint: no such file or directory"
  Normal  Pulled  12m (x106 over 36m)  kubelet, cam-src-8320-v2ksq-worker-northcentralus-67q7l  Container image "quay-enterprise-quay-enterprise.apps.cam-tgt-8320.qe.azure.devcluster.openshift.com/admin/openshift-migration-hook-runner-rhel7@sha256:fda22f17e8e019e47b09c2e5dc06743bcae2f38fe0e81180850baf7eae2d5263" already present on machine



Expected results:
The hook should be executed without problems, and the migration should finish without problems too.

Additional info: