Helptext is shown after all errors

[r2d4]

$ skaffold run
Starting build...
Error: running skaffold steps: build: build step: running build for artifact: Could not find dockerfile: Dockerfile
Usage:
  skaffold run [flags]

Flags:
  -f, --filename string       Filename or URL to the pipeline file (default "skaffold.yaml")
  -h, --help                  help for run
  -p, --profile stringArray   Activate profiles by name
  -t, --tag string            The optional custom tag to use for images which overrides the current Tagger configuration
      --toot                  Emit a terminal beep after the deploy is complete

Global Flags:
  -v, --verbosity string   Log level (debug, info, warn, error, fatal, panic (default "warning")

[dgageot]

Fixed with #449