Build functest-parser for arm64 via travis-ci

Build functest-parser for arm64 via travis-ci

Even if clearwater-live-test dependencies have been updated [1], the
next containers can be built for ARM (ruby raises SEGFAULT via
qemu-user-static):
  - functest-vnf
  - functest-restapi

The related manifest is also updated.

[1] https://gerrit.opnfv.org/gerrit/#/c/50295/8

Conflicts:
    .travis.yml

Change-Id: Ie1eb78436a3da5eb7b5c1028b7f8323e8c3e73a2
Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>
(cherry picked from commit 12c99c5f3fef126283e3a9795c4c1d436cc7846f)