do not destroy the mutex and condition before we have used to to join with all slaves

Signed-off-by: Mattias Andrée <maandree@operamail.com>
m + ignore EINTR when sending a message

Signed-off-by: Mattias Andrée <maandree@operamail.com>
m

Signed-off-by: Mattias Andrée <maandree@operamail.com>