Remove Ubuntu 16.04 arm packer job

We are fully migrating to Ubuntu 18.04 and
all arm jobs are now migrated and tested.

Change-Id: I390d396506e1db531948aa419a2451c1b6e716f1
Issue-ID: CIMAN-33
Signed-off-by: Jessica Wagantall <jwagantall@linuxfoundation.org>
1 file changed