mailbox : fix using global var instead of local

    if not changed mailbox will go nuts after being set to suspended

Signed-off-by: Oscar Suro <outercript@gmail.com>
mailbox : corrected mailbox handlers not setting correct task state

    after a mesage is read/written tell the other task that the resource
    is ready if it is still waiting for it

Signed-off-by: Oscar Suro <outercript@gmail.com>