Enhanced del-volume.py
Enhanced del-volume.py

* added error message if name not found in delete by name
* updated help format

miqui/python-hpOneView,andreadean5/python-hpOneView,danielreed/python-hpOneView,ufcg-lsd/python-hpOneView,HewlettPackard/python-hpOneView,HewlettPackard/python-hpOneView