Manually repair regenerated sample config
    
    tools/config/generate_sample.sh did not include Oslo libraries listed in
    tools/config/oslo.config.generator.rc
    Merge sample config generated with oslo-config-generator for:
    namespace = oslo.messaging
    namespace = oslo.db
    namespace = oslo.concurrency
    namespace = oslo.log
    
    Change-Id: I53e9b8895aa1c745f1c7d57ee5977ed02da3e40c