convert vm name to str

[tatref]

On Python2.7, vm_from_list is not a str but a unicode object
Fixes #71

I'm not sure if this is a correct fix, or if every field in Config should be converted to str?

oVirtBackup/config.py

Lines 35 to 57 in b9d7005

	self.__vm_names = json.loads(config_parser.get(section, "vm_names"))
	self.__vm_middle = config_parser.get(section, "vm_middle")
	self.__vm_suffix = "_"
	self.clear_vm_suffix
	self.__server = config_parser.get(section, "server")
	self.__username = config_parser.get(section, "username")
	self.__password = config_parser.get(section, "password")
	self.__snapshot_description = config_parser.get(section, "snapshot_description")
	self.__cluster_name = config_parser.get(section, "cluster_name")
	self.__datacenter_name = config_parser.get(section, "datacenter_name")
	self.__export_domain = config_parser.get(section, "export_domain")
	self.__timeout = config_parser.getint(section, "timeout")
	self.__backup_keep_count = config_parser.get(section, "backup_keep_count")
	self.__backup_keep_count_by_number = config_parser.get(section, "backup_keep_count_by_number")
	self.__dry_run = config_parser.getboolean(section, "dry_run")
	self.__debug = debug
	self.__vm_name_max_length = config_parser.getint(section, "vm_name_max_length")
	self.__use_short_suffix = config_parser.getboolean(section, "use_short_suffix")
	self.__storage_domain = config_parser.get(section, "storage_domain")
	self.__storage_space_threshold = config_parser.getfloat(section, "storage_space_threshold")
	self.__logger_fmt = config_parser.get(section, "logger_fmt")
	self.__logger_file_path = config_parser.get(section, "logger_file_path")
	self.__persist_memorystate = config_parser.getboolean(section, "persist_memorystate")

[wefixit-AT]

please check the conflicts