Description of problem:
Wrong error message when trying to import from private registry with TLS certificate which is NOT signed by a trusted CA

Version-Release number of selected component (if applicable):
4.9

How reproducible: 100%

Steps to Reproduce:
1. Create and add a docker image and upload it to the private registry.
2. Ensure your registry TLS certificate, which is NOT signed by a trusted CA, resides in a file named 'my-registry.crt'
3. Create a ConfigMap containing all certificates required to trust the registry. e.g 'kubectl create configmap my-registry-certs --from-file=my-registry.crt'
4. Import the image from the registry - Import should succeed
5. Remove the certificate previously added to the config map
6. Attempt to import the image again - Import should fail

Actual results:

	Containers:
	  importer:
	    ........
	    Args:
	      -v=1
	    State:          Waiting
	      Reason:       CrashLoopBackOff
	    Last State:     Terminated
	      Reason:       Error
	      Message:      /github.com/containers/image/v5/docker/docker_client.go:759 github.com/containers/image/v5/docker.(*dockerClient).makeRequest   /remote-source/app/vendor/github.com/containers/image/v5/docker/docker_client.go:421 github.com/containers/image/v5/docker.(*dockerImageSource).fetchManifest   /remote-source/app/vendor/github.com/containers/image/v5/docker/docker_image_src.go:189 github.com/containers/image/v5/docker.(*dockerImageSource).ensureManifestIsLoaded   /remote-source/app/vendor/github.com/containers/image/v5/docker/docker_image_src.go:223 github.com/containers/image/v5/docker.newImageSourceAttempt   /remote-source/app/vendor/github.com/containers/image/v5/docker/docker_image_src.go:127 github.com/containers/image/v5/docker.newImageSource   /remote-source/app/vendor/github.com/containers/image/v5/docker/docker_image_src.go:69 github.com/containers/image/v5/docker.dockerReference.NewImageSource   /remote-source/app/vendor/github.com/containers/image/v5/docker/docker_transport.go:144 kubevirt.io/containerized-data-importer/pkg/importer.readImageSource   /remote-source/app/pkg/importer/transport.go:73 kubevirt.io/containerized-data-importer/pkg/importer.copyRegistryImage   /remote-source/app/pkg/importer/transport.go:179 kubevirt.io/containerized-data-importer/pkg/importer.CopyRegistryImage   /remote-source/app/pkg/importer/transport.go:227 kubevirt.io/containerized-data-importer/pkg/importer.(*RegistryDataSource).Transfer   /remote-source/app/pkg/importer/registry-datasource.go:83 kubevirt.io/containerized-data-importer/pkg/importer.(*DataProcessor).ProcessDataWithPause   /remote-source/app/pkg/importer/data-processor.go:190 kubevirt.io/containerized-data-importer/pkg/importer.(*DataProcessor).ProcessData   /remote-source/app/pkg/importer/data-processor.go:165 main.main   /remote-source/app/cmd/cdi-importer/importer.go:189 runtime.main   /usr/lib/golang/src/runtime/proc.go:204 runtime.goexit   /usr/lib/golang/src/runtime/asm_amd64.s:1374 Could not create image reference kubevirt.io/containerized-data-importer/pkg/importer.readImageSource   /remote-source/app/pkg/importer/transport.go:76 kubevirt.io/containerized-data-importer/pkg/importer.copyRegistryImage   /remote-source/app/pkg/importer/transport.go:179 kubevirt.io/containerized-data-importer/pkg/importer.CopyRegistryImage   /remote-source/app/pkg/importer/transport.go:227 kubevirt.io/containerized-data-importer/pkg/importer.(*RegistryDataSource).Transfer   /remote-source/app/pkg/importer/registry-datasource.go:83 kubevirt.io/containerized-data-importer/pkg/importer.(*DataProcessor).ProcessDataWithPause   /remote-source/app/pkg/importer/data-processor.go:190 kubevirt.io/containerized-data-importer/pkg/importer.(*DataProcessor).ProcessData   /remote-source/app/pkg/importer/data-processor.go:165 main.main   /remote-source/app/cmd/cdi-importer/importer.go:189 runtime.main   /usr/lib/golang/src/runtime/proc.go:204 runtime.goexit   /usr/lib/golang/src/runtime/asm_amd64.s:1374 Failed to read registry image kubevirt.io/containerized-data-importer/pkg/importer.(*RegistryDataSource).Transfer   /remote-source/app/pkg/importer/registry-datasource.go:85 kubevirt.io/containerized-data-importer/pkg/importer.(*DataProcessor).ProcessDataWithPause   /remote-source/app/pkg/importer/data-processor.go:190 kubevirt.io/containerized-data-importer/pkg/importer.(*DataProcessor).ProcessData   /remote-source/app/pkg/importer/data-processor.go:165 main.main   /remote-source/app/cmd/cdi-importer/importer.go:189 runtime.main   /usr/lib/golang/src/runtime/proc.go:204 runtime.goexit   /usr/lib/golang/src/runtime/asm_amd64.s:1374 Unable to transfer source data to scratch space kubevirt.io/containerized-data-importer/pkg/importer.(*DataProcessor).ProcessDataWithPause   /remote-source/app/pkg/importer/data-processor.go:195 kubevirt.io/containerized-data-importer/pkg/importer.(*DataProcessor).ProcessData   /remote-source/app/pkg/importer/data-processor.go:165 main.main   /remote-source/app/cmd/cdi-importer/importer.go:189 runtime.main   /usr/lib/golang/src/runtime/proc.go:204 runtime.goexit   /usr/lib/golang/src/runtime/asm_amd64.s:1374
	      Exit Code:    1
	      Started:      Wed, 01 Sep 2021 17:38:21 +0000
	      Finished:     Wed, 01 Sep 2021 17:38:22 +0000
	    Ready:          False


Expected results:

	Containers:
	  importer:
	    ........
	    Args:
	      -v=1
	    State:          Terminated
	      Reason:       Error
	      Message:      Unable to process data: Get "URL:8443/v2/": x509: certificate signed by unknown authority
	      Exit Code:    1
	      Started:      Wed, 01 Sep 2021 17:39:38 +0000
	      Finished:     Wed, 01 Sep 2021 17:39:39 +0000
	    Last State:     Terminated
	      Reason:       Error
	      Message:      Unable to process data: Get "URL:8443/v2/": x509: certificate signed by unknown authority
	      Exit Code:    1
	      Started:      Wed, 01 Sep 2021 17:39:12 +0000
	      Finished:     Wed, 01 Sep 2021 17:39:13 +0000
	    Ready:          False


Additional info:
Use this command to describe the importing pod and see the error message:
oc describe pod -n cdi-import-test-import-registr