Install bzip2 on RHEL 7 and Fedora hosts

The backup script needs the bzcat command, which does not come
installed on RHEL 7 and Fedora hosts by default. This patch installs
the bzip2 package before attempting to run tests that use bzcat.
Merge pull request #580 from cmurphy/fix_bzcat

Install bzip2 on RHEL 7 and Fedora hosts