Added command to docker role to update yum cache and accept new repo GPG keys.
Added command to docker role to update yum cache and accept new repo GPG keys.

StanfordBioinformatics/loom,StanfordBioinformatics/loom,StanfordBioinformatics/xppf,StanfordBioinformatics/loom,StanfordBioinformatics/xppf,StanfordBioinformatics/loom,StanfordBioinformatics/xppf,StanfordBioinformatics/xppf