Switch to OPNFV Clearwater repository

Switch to OPNFV Clearwater repository

Project Clearwater is backed by Metaswitch Networks [1].
They will therefore not be reinstating the 14.04 Project Clearwater
repo server.

Then all binaries have been compiled and published on
http://artifacts.opnfv.org/functest/clearwater/debian

Then it updates sources.list.d/clearwater.list

[1] https://www.projectclearwater.org/

Change-Id: I529e59f8aeeafb96bafb7da8a1cce5c4c5a9e031
Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>
(cherry picked from commit 0159c469d752fd41876c81995e113562650f73a0)