[API] Fix daemon config reference

Change-Id: I34f9835a25cc37067a085b013c8dcf69376dec74
Use ConfigParser for database config parsing

We cannot use oslo.config for the database sections because we
would need to register the section names before parsing, which
is not possible since the section names are dynamically defined.

Change-Id: Icaf9b02119159922492617bfdc87bbc2c5a03dbe