Remove redundant arping package from apts/nova

Nova is dependent on arping because 'arping -U' is used.
Arping package doesn't provide 'arping -U'. Let iputils-arping
do the arping job.

Change-Id: Iad4cbf823881de4656fb6a4e32285cf2a49b1d2a
Merge "Remove redundant arping package from apts/nova"