RHEVM : Upgrade error from RHEV 3.5 to 3.6 results in keyError

Issue

• Engine-setup command exits with setup failed error

        Please confirm installation settings (OK, Cancel) [OK]: 
[ INFO  ] Cleaning async tasks and compensations
[ ERROR ] Failed to execute stage 'Setup validation':  '235'
[ INFO  ] Stage: Clean up
          Log file is located at /var/log/ovirt-engine/setup/ovirt-engine-setup-20150311132601-nkrll6.log
[ INFO  ] Generating answer file '/var/lib/ovirt-engine/setup/answers/20150311132820-setup.conf'
[ INFO  ] Stage: Pre-termination
[ INFO  ] Stage: Termination
[ ERROR ] Execution of setup failed