Use Centos vars from common-packer

Use vars/centos-7.json from common packer instead
of using the local file.

Change-Id: I86386b0ac932ea08a33ac5efbd5184932d560d9d
Issue-ID: CIMAN-34
Signed-off-by: Jessica Wagantall <jwagantall@linuxfoundation.org>
1 file changed