Reenabled acq_expires SA timer using rekey timeout

While not using a SA expiration for allocating SPIs works fine,
the situation is much more problematic for kernel-created temporary
SAs from acquires. If the negotiation of such a CHILD_SA fails,
the created temporary SA can not be deleted.

src/charon/plugins/kernel_netlink/kernel_netlink_ipsec.c

@@ -1996,7 +1996,7 @@ kernel_netlink_ipsec_t *kernel_netlink_ipsec_create()
 	fd = open("/proc/sys/net/core/xfrm_acq_expires", O_WRONLY);
 	if (fd)
 	{
-		ignore_result(write(fd, "0", 1));
+		ignore_result(write(fd, "165", 3));
 		close(fd);
 	}