Fix scoping issues with site variables

move heat_hash, murano_hash, sevanna_hash to local scope
correct scope for use_ceph
remove duplicate use_cep in site.pp
fix savanna $quantum ref -> $::use_quantum
add else to end of fuel_settings['nodes'] in site.pp
- fail to catch verry bad case of empty nodes
Merge pull request #634 from xarses/fix_scoped_vars

Fix scoping issues with site variables breaking deployment