fix name 'update_volume_status' to 'update_volume_stats'

_update_volume_status() private method is called by
get_volume_stats(). This is confusing as the volume's
stats and not status gets updated.

fixes bug #1199327

Change-Id: I9f7971e457250798320c14d3f58bdc199c8cfceb
Using volume name property instead of using template and id.

Change-Id: I478f875ed509fb591799a78b7fd52bc830e6fd1c
Merge "fix name 'update_volume_status' to 'update_volume_stats'"
Merge "Using volume name property instead of using template and id."