Also remove mdadm-ptest as it is already included in the slow list.
(From OE-Core rev: 18b7e4c05a54ea0dde21b60b8bef8dcb9ccf4e7e)
Signed-off-by: Alexander Kanavin <alex.kanavin@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>