"Pod spec does not contain a template container called 'task-runner'" error message swallowed

[dturn]

Noticed this when messing around with something else. The runner fails, but the lack of reason is a bit frustrating. I'm working on a fix.

cc: @KnVerey

[INFO][2018-10-25 17:10:32 -0700]	
[INFO][2018-10-25 17:10:32 -0700]	-------------------------------------Phase 1: Initializing task-------------------------------------
[INFO][2018-10-25 17:10:32 -0700]	Validating configuration
[INFO][2018-10-25 17:10:32 -0700]	Using namespace 'k8sdeploy-test-run-with-pod-spec-template-miss-16381c175df4feeb' in context 'minikube'
[INFO][2018-10-25 17:10:32 -0700]	Using template 'hello-cloud-template-runner'
[INFO][2018-10-25 17:10:32 -0700]	
[INFO][2018-10-25 17:10:32 -0700]	------------------------------------------Result: FAILURE-------------------------------------------
[INFO][2018-10-25 17:10:32 -0700]	
[INFO][2018-10-25 17:10:32 -0700]	-------------------------------------Phase 1: Initializing task-------------------------------------
[INFO][2018-10-25 17:10:32 -0700]	Validating configuration
[INFO][2018-10-25 17:10:32 -0700]	Using namespace 'k8sdeploy-test-run-with-pod-spec-template-miss-16381c175df4feeb' in context 'minikube'
[INFO][2018-10-25 17:10:32 -0700]	Using template 'hello-cloud-template-runner'
[INFO][2018-10-25 17:10:32 -0700]	
[INFO][2018-10-25 17:10:32 -0700]	------------------------------------------Result: FAILURE-------------------------------------------

[KnVerey]

Yep, that's probably a regression from the refactoring we did to the runner in adding log streaming. FYI I have a WIP branch to improve and centralize validations for all our tasks: https://github.com/Shopify/kubernetes-deploy/compare/config_validator. I think it's ok to make a quick fix + regression test here and then I'll make sure my PR covers the root cause of us not noticing this.