kubectl error messages are suppressed

[ahmetb]

skaffold v0.6.0

when kubectl apply fails, its stderr is omitted from skaffold dev output and it gives this:

Starting deploy...
service "clusterregistry" created
configmap "gcp-project" created
configmap "corefile" created
service "dns-server" created
WARN[0280] run: deploy: deploy step: deploying manifests: exit status 1
Watching for changes...

and it actually doesn't start the watch.

This is very hard to debug as I have to apply every single manifest file to see which one is failing and why.

[dgageot]

@ahmetb it's fixed in master.

[dlorenc]

#560