Avoid duplicated/cancelled deployments when processing custom templates using external private registries

Issue

Processing custom templates with oc process "some-template" | oc apply -f - with customized imagestreams to store image information from external private registries and ImageChange triggers creates duplicated replicationControllers, with the first being cancelled with:

openshift.io/deployment.cancelled=true
openshift.io/deployment.phase=Failed
openshift.io/deployment.replicas=0
openshift.io/deployment.status-reason=newer deployment was found running

And second completed successfully with:

openshift.io/deployment.phase=Complete
openshift.io/deployment.replicas=
openshift.io/deployment.status-reason=image change