Description of problem:
When trying to extract openshift-install from content in a mirrored local registry, it still tries to go to quay.io.

This is the case even when adding --from=<mirror>, which the docs do not currently specify.


Version-Release number of selected component (if applicable):
4.3.3


How reproducible:
100%


Steps to Reproduce:
1. Mirror all content per restricted network install docs
2. Run something like `oc adm release extract -a $HOME/merged_pullsecret.json --command=openshift-install --from="utilityvm.example.com:5000/ocp4/openshift4:4.3.3-x86_64" --loglevel=3`
3.

Actual results:
I0317 23:00:09.816174   17887 extract_tools.go:323] Will extract usr/bin/openshift-install from quay.io/openshift-release-dev/ocp-v4.0-art-dev@sha256:acce9b9a378b03e7e2130f65067a7c3a45a90e18653be8665e1534e9e5b63fcb


Expected results:
should be extracted from the mirror


Additional info:
[nstephan@bastion ~]$ oc adm release extract -a $HOME/merged_pullsecret.json --command=openshift-install --from="utilityvm.example.com:5000/ocp4/openshift4:4.3.3-x86_64" --loglevel=3
I0316 12:31:06.659751   13546 extract_tools.go:315] Skipping openshift-install-mac-%s.tar.gz, does not match current OS darwin
I0316 12:31:06.659829   13546 extract_tools.go:323] Will extract usr/bin/openshift-install from quay.io/openshift-release-dev/ocp-v4.0-art-dev@sha256:acce9b9a378b03e7e2130f65067a7c3a45a90e18653be8665e1534e9e5b63fcb
I0316 12:31:10.259132   13546 extract_tools.go:681] Found match for release version at 3026 (len=4096, offset=327, n=3769)
I0316 12:31:10.264032   13546 extract_tools.go:681] Found match for release image at 2216 (len=4096, offset=327, n=3769)



The image is there, though:

[nstephan@bastion ~]$ podman pull utilityvm.example.com:5000/ocp4/openshift4@sha256:acce9b9a378b03e7e2130f65067a7c3a45a90e18653be8665e1534e9e5b63fcb
Trying to pull utilityvm.example.com:5000/ocp4/openshift4@sha256:acce9b9a378b03e7e2130f65067a7c3a45a90e18653be8665e1534e9e5b63fcb...Getting image source signatures
Copying blob 455ea8ab0621 skipped: already exists
Copying blob bb13d92caffa skipped: already exists
Copying blob 13be0effd90b skipped: already exists
Copying blob edf561fefe18 skipped: already exists
Copying blob 801c9fc3ed45 done
Copying config 9ab59172b7 done
Writing manifest to image destination
Storing signatures
9ab59172b71673bd8bf414d7d9b2d9338ad2189dfab5d11fc95d6390f01d7290



Same with both 4.2 and 4.3 clients, but this test was:

[nstephan@bastion ~]$ oc version
Client Version: 4.3.3
Server Version: 4.3.3
Kubernetes Version: v1.16.2