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
diff --git a/files/apts/nova b/files/apts/nova
index f4615c4..298e25f 100644
--- a/files/apts/nova
+++ b/files/apts/nova
@@ -2,8 +2,7 @@
 dnsmasq-utils # for dhcp_release only available in dist:oneiric,precise,quantal
 kpartx
 parted
-arping # only available in dist:natty
-iputils-arping # only available in dist:oneiric
+iputils-arping
 mysql-server # NOPRIME
 python-mysqldb
 python-xattr # needed for glance which is needed for nova --- this shouldn't be here