Description of problem:
Tag a image which requires Http, failed  to pull the image through docker-registry, met not-found error.

Version-Release number of selected component (if applicable):
openshift v1.1.4-124-g847bcc2
kubernetes v1.2.0-36-g4a3f9c5
etcd 2.2.5

How reproducible:
Always

Steps to Reproduce:
1. Run a private registy to use http protocal;
  `docker run -d -p 5000:5000 registry` 
2. Push the image :busybox to private registry;
   `docker tag busybox localhost:5000/busybox`
   `docker push localhost:5000/busybox`
3. Login OpenShift and create project;
4. Use command to tag the image from private registry;
   `oc tag 172.18.11.76:5000/busybox  mytest:v2 --insecure=true`
5. Use the user token to login docker-registry;
6. Try to pull the image through docker-registry;

Actual results:
6. Failed to image which requires HTTP through docker-registry
oc get is
NAME      DOCKER REPO                     TAGS      UPDATED
mytest    172.30.29.6:5000/zhouy/mytest   v2        5 minutes ago

docker pull 172.30.29.6:5000/zhouy/mytest:v2
Trying to pull repository 172.30.29.6:5000/zhouy/mytest ... not found
Error: image zhouy/mytest:v2 not found

Expected results:
Should succeed to pull image which requires HTTP through docker-registry

Additional info:
oc logs -f dc/docker-registry 
time="2016-03-18T10:35:52.967152098Z" level=error msg="Error parsing digest \"f1e4b055fb652a75379f41aee7b23a23a5f6dcc3b07e61f181d542ebb04f2ac9\": invalid checksum digest format" go.version=go1.4.2 http.request.host="172.30.241.110:5000" http.request.id=b59f304f-959b-42b6-bb2f-9a6a649f0592 http.request.method=GET http.request.remoteaddr="172.18.13.53:55043" http.request.uri="/v2/zhouy/mytest/manifests/v2" http.request.useragent="docker/1.9.1 go/go1.4.2 kernel/3.10.0-229.7.2.el7.x86_64 os/linux arch/amd64" instance.id=07c748fa-a30b-4789-8991-c4e43759da55 vars.name="zhouy/mytest" vars.reference=v2 
time="2016-03-18T10:35:52.967252139Z" level=error msg="response completed with error" err.code="MANIFEST_UNKNOWN" err.detail="invalid checksum digest format" err.message="manifest unknown" go.version=go1.4.2 http.request.host="172.30.241.110:5000" http.request.id=b59f304f-959b-42b6-bb2f-9a6a649f0592 http.request.method=GET http.request.remoteaddr="172.18.13.53:55043" http.request.uri="/v2/zhouy/mytest/manifests/v2" http.request.useragent="docker/1.9.1 go/go1.4.2 kernel/3.10.0-229.7.2.el7.x86_64 os/linux arch/amd64" http.response.contenttype="application/json; charset=utf-8" http.response.duration=173.095437ms http.response.status=404 http.response.written=82 instance.id=07c748fa-a30b-4789-8991-c4e43759da55 vars.name="zhouy/mytest" vars.reference=v2 
172.18.13.53 - - [18/Mar/2016:10:35:52 +0000] "GET /v2/zhouy/mytest/manifests/v2 HTTP/1.1" 404 82 "" "docker/1.9.1 go/go1.4.2 kernel/3.10.0-229.7.2.el7.x86_64 os/linux arch/amd64"
172.18.13.53 - - [18/Mar/2016:10:35:52 +0000] "GET /v1/repositories/zhouy/mytest/images HTTP/1.1" 404 19 "" "docker/1.9.1 go/go1.4.2 kernel/3.10.0-229.7.2.el7.x86_64 os/linux arch/amd64"