Create dumpfile from postgres database, and return filename.

def dump_database(self):
        """ Create dumpfile from postgres database, and return filename. """
        db_file = self.create_file_name(self.databases['source']['name'])
        self.print_message("Dumping postgres database '%s' to file '%s'"
                           % (self.databases['source']['name'], db_file))
        self.export_pgpassword('source')
        args = [
            "pg_dump",
            "-Fc",
            "--no-acl",
            "--no-owner",
            "--dbname=%s" % self.databases['source']['name'],
            "--file=%s" % db_file,
        ]
        args.extend(self.databases['source']['args'])
        subprocess.check_call(args)
        return db_file