There are three different priorities for applying env variables:
1) environment/config file environment variables
2) image's config
3) user overrides (--env)
The third kind are known to the client, while the default config and image's
config is handled by the backend.
Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>
Signed-off-by: Daniel J Walsh <dwalsh@redhat.com>