contrib/docker/fedora21

gpg: use 'wvfs' instead of 'wfile'

Method is about to be deprecated and the modern form is shorter.

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