Delete the right dir when building functest-vnf
Delete the right dir when building functest-vnf

It reduces a lot the size of the docker image.

Change-Id: Ifd577169697b33dfd89594e8dd3afe4aa34ec7f9
Signed-off-by: Cédric Ollivier <d48310251a4a484d041bc5d09a9ac4d86d20f793@orange.com>

opnfv/functest,opnfv/functest