Remove functest_defcore testcases
Remove functest_defcore testcases

refstack_defcore has been merged
the testcase is no more needed (duplication)

Change-Id: I287406b40cdd89ff2c4eadcde7e9d5a93e21953a
Signed-off-by: Morgan Richomme <863ecccd07b4194c40ddc432b982c8c67e56599a@orange.com>

opnfv/functest,opnfv/functest,mywulin/functest,mywulin/functest