Clean functest-kubernetes jjb

It removes all debug data added by "Add debugs when calling gsutil"
[1] and "Print debug infos in functest-kubernetes jjbs" [2]

The issue came from former data dirs in http://artifacts.opnfv.org/
which changes logics [3]. All kubernetes latest results were removed
to solve the issues.

[1] https://gerrit.opnfv.org/gerrit/#/c/68145/
[2] https://gerrit.opnfv.org/gerrit/#/c/68113/
[3] https://cloud.google.com/storage/docs/gsutil/commands/cp

Change-Id: I4be465b0b6f63bcd77e46440da715d4269d4e79f
Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>