When the `inject` command is used on a YAML file that is invalid, it prints out an invalid YAML file with the injected proxy. This may give a false indication to the user that the inject was successful even though the inject command prints out an error message further down the terminal window. This PR fixes#303 and contains a test input and output file that indicates what should be shown.
This PR also fixes#390.
Signed-off-by: Dennis Adjei-Baah <dennis@buoyant.io>
Dennis Adjei-Baah