Print the stack traceback when cleaning juju_epc
Print the stack traceback when cleaning juju_epc

Change-Id: If32557a4384cafd67b7c294f8c0592ee2769b1a5
Signed-off-by: Cédric Ollivier <d48310251a4a484d041bc5d09a9ac4d86d20f793@orange.com>

opnfv/functest,opnfv/functest