new-app: accept template on stdin

[csrwng]

new-app should not throw an error when passing a template on stdin
it currently breaks because isSingle is returned as false by the builder, even though there is only a single object in the list.

Fixes #8555

[csrwng]

@bparees ptal

[bparees]

why is there a list at all? isn't it a single template?

[csrwng]

why is there a list at all? isn't it a single template?

because if the input is a stream, the resource builder will put whatever it reads into a list and always sets isSingular to false:
https://github.com/openshift/origin/blob/master/vendor/k8s.io/kubernetes/pkg/kubectl/resource/builder.go#L669

[bparees]

ok, thanks... lgtm
[merge]

[openshift-bot]

continuous-integration/openshift-jenkins/merge SUCCESS (https://ci.openshift.redhat.com/jenkins/job/test_pr_origin/7352/) (Image: devenv-rhel7_4724)

[openshift-bot]

Evaluated for origin merge up to ac5405c

[openshift-bot]

[Test]ing while waiting on the merge queue

[openshift-bot]

Evaluated for origin test up to ac5405c

[openshift-bot]

continuous-integration/openshift-jenkins/test SUCCESS (https://ci.openshift.redhat.com/jenkins/job/test_pr_origin/7352/)