Handle SIGPIPE in req_setup_send

When IPC client exits exactly when req_setup_send function calls send,
SIGPIPE is generated and corosync (because SIGPIPE is not handled)
exits. Solution is to use MSG_NOSIGNAL as flag.

Signed-off-by: Jan Friesse <jfriesse@redhat.com>
Reviewed-by: Fabio M. Di Nitto <fdinitto@redhat.com>
confdb: Make objdb_notify_dispatch preemptable

objdb_notify_dispatch traverse thru confdb_ipc_message_holder_list list
until it's empty. If IPC connection is still feeding confdb/objdb with
changes then iteration will never end. To prevent this and let corosync
properly preempt, terminal condition is enhanced with maximum number of
processed items from list. Change makes confdb preemptable so corosync
can accept new connections, receive/send token, ...

Signed-off-by: Jan Friesse <jfriesse@redhat.com>
Reviewed-by: Fabio M. Di Nitto <fdinitto@redhat.com>