(pdb-80)(packaging) Fixup logic in defaults file for java on EL

On EL {5,6} X86_64 platforms, the direct path to the java-1.7.0-openjdk binaries has
an arch-specific component. This PR adds logic to the /etc/defaults/puppetdb file to
support accessing that path.
Merge pull request #862 from shrug/bug/1.6.x/openjdk

(pdb-80)(packaging) Fixup logic in defaults file for java on EL