'Create the Task for the attach disk to instance method.
Requires disk info through requirement of disk_dev_info (provided by
crt_disk_from_img)
:param disk_dvr: The disk driver.
:param instance: The nova instance.
:param stg_ftsk: FeedTask to defer storage connectivity operations.'

def __init__(self, disk_dvr, instance, stg_ftsk):

    super(AttachDisk, self).__init__('attach_disk', requires=['disk_dev_info'])
    self.disk_dvr = disk_dvr
    self.instance = instance
    self.stg_ftsk = stg_ftsk
