package/systemd: security bump to version 247.9

Fixes the following security issues:

- CVE-2020-13529: An exploitable denial-of-service vulnerability exists in
  Systemd 245.  A specially crafted DHCP FORCERENEW packet can cause a
  server running the DHCP client to be vulnerable to a DHCP ACK spoofing
  attack.  An attacker can forge a pair of FORCERENEW and DCHP ACK packets
  to reconfigure the server.
  https://talosintelligence.com/vulnerability_reports/TALOS-2020-1142

- CVE-2021-33910: Denial of Service (Stack Exhaustion) in systemd (PID 1)
  https://blog.qualys.com/vulnerabilities-threat-research/2021/07/20/cve-2021-33910-denial-of-service-stack-exhaustion-in-systemd-pid-1

Update hash of README for a change of IRC network:
-        #systemd on irc.freenode.org
+        #systemd on irc.libera.chat

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/systemd/systemd.hash

@@ -1,6 +1,6 @@
 # sha256 locally computed
-sha256  2869986e219a8dfc96cc0dffac66e0c13bb70a89e16b85a3948876c146cfa3e0  systemd-247.3.tar.gz
+sha256  629b8c895efa000b921092c7a565680c66dcd0ec74ed11cb2dd2b6701492675d  systemd-247.9.tar.gz
 sha256  ab15fd526bd8dd18a9e77ebc139656bf4d33e97fc7238cd11bf60e2b9b8666c6  LICENSE.GPL2
 sha256  dc626520dcd53a22f727af3ee42c770e56c97a64fe3adb063799d8ab032fe551  LICENSE.LGPL2.1
-sha256  6f22d19d35b00f35e0444e0bc9139e6d3bdf7277978f89c4e175e37b18c43f3d  README
+sha256  996b2bd286a6832b4c8cbab8e662d371e2fd061a2e14925bc6099d805f12c7a3  README
 sha256  83bb6bd9ccd2cf5230cb1807ed16258289768dc4d9cb80069a814e04415a1275  tools/chromiumos/LICENSE

package/systemd/systemd.mk

@@ -4,7 +4,7 @@
 #
 ################################################################################
 
-SYSTEMD_VERSION = 247.3
+SYSTEMD_VERSION = 247.9
 SYSTEMD_SITE = $(call github,systemd,systemd-stable,v$(SYSTEMD_VERSION))
 SYSTEMD_LICENSE = LGPL-2.1+, GPL-2.0+ (udev), Public Domain (few source files, see README), BSD-3-Clause (tools/chromiumos)
 SYSTEMD_LICENSE_FILES = LICENSE.GPL2 LICENSE.LGPL2.1 README tools/chromiumos/LICENSE