contrib/docker/fedora21

exchange: support for streaming clone bundles

Now that we have a mechanism to produce and consume streaming clone
bundles, we need to teach the human-facing bundle specification parser
and the internal bundle file header reading code to be aware of this new
format. This patch does so.

For the human-facing bundle specification, we choose the name "packed"
to describe "streaming clone bundles" because the bundle is essentially
a "pack" of raw revlog files that are "packed" together. There should
probably be a bikeshed over the name, especially since it is human
facing.

FROM fedora:21
RUN yum install -y gcc
RUN yum install -y python-devel python-docutils
RUN yum install -y make
RUN yum install -y rpm-build
RUN yum install -y gettext
# For creating repo meta data
RUN yum install -y createrepo