Add support for GCP_OAUTH2_REFRESH_TOKEN env variable.

This addresses #8.

Also:
* Be more robust about detecting GCE service account scopes. (#5)
* Clarify different auth methods in README.md
Yes. http://en.m.wikipedia.org/wiki/Fully_qualified_domain_name
On Jun 25, 2014 2:39 AM, "Johan Euphrosine" <notifications@github.com>
wrote:

> In run.sh:
>
> > +gs_oauth2_refresh_token = $GCP_OAUTH2_REFRESH_TOKEN
> > +EOF
> > +  BOTO_PATH=/etc/boto.cfg
> > +  echo "Using credentails specified in GCP_OAUTH2_REFRESH_TOKEN env variable"
> > +fi
> > +
> > +# Look to see if something is mounted under the /.config dir
> > +if [[ -z "${BOTO_PATH}" ]]; then
> > +  BOTO_PATH=${BOTO_PATH:-$(find /.config | grep .boto | head -n 1)}
> > +fi
> > +
> > +if [[ -n "${BOTO_PATH}" ]]; then
> > +  echo "Using credentials in ${BOTO_PATH}"
> > +else
> > +  wget -q --header='Metadata-Flavor: Google' \
> > +    http://metadata.google.internal./computeMetadata/v1/instance/service-accounts/default/scopes \
>
> @jbeda <https://github.com/jbeda> was the extra . after google.internal
> intentional?
>
> —
> Reply to this email directly or view it on GitHub
> <https://github.com/GoogleCloudPlatform/docker-registry/pull/9/files#r14172398>
> .
>