Fix domain database initialization
    
    To fix bug 1089916, calls to db_api.configure_db() were changed to
    setup_db_env(). However, the gateway domain initialization didn't get
    the memo. This patch makes sure setup_db_env() is called in all the
    relevant places.
    
    Fixes bug 1131705.
    
    Change-Id: Ieec141192b8a5a045dadba6d70abaa25748b85b2