Added a tag to FROM fedora (fedora:20)

Docker-DCO-1.1-Signed-off-by: William Henry <whenry@redhat.com> (github: ipbabble)

contrib/man/md/Dockerfile

@@ -1,4 +1,4 @@
-FROM fedora
+FROM fedora:20
 MAINTAINER ipbabble <emailwhenry@redhat.com>
 # Update and install pandoc
 RUN yum -y update; yum clean all;