systemd: Add fix for systemd-networkd crash during free

We are observing systemd-network service crash during link down
while freeing link->ifname pointer

Backtrace:
(gdb) bt
0  __GI_abort () at abort.c:107
1  0x0000007f861d32b4 in __libc_message (action=action@entry=do_abort, fmt=fmt@entry=0x7f8628d500 "%s\n") at ../sysdeps/posix/libc_fatal.c:155
2  0x0000007f861da51c in malloc_printerr (str=str@entry=0x7f86289070 "free(): invalid next size (fast)") at malloc.c:5347
3  0x0000007f861dbd58 in _int_free (av=0x7f862c9a28 <main_arena>, p=0x558aa28eb0, have_lock=0) at malloc.c:4249
4  0x0000005569249cf0 in link_free (link=0x558aa1c0d0) at ../git/src/network/networkd-link.c:715
5  link_unref (p=0x558aa1c0d0) at ../git/src/network/networkd-link.c:734
6  0x000000556920f34c in manager_rtnl_process_link (rtnl=<optimized out>, message=0x558aa2a430, userdata=0x558a9fc630)

While checking upstream code change with regards to link->ifname
memory allocation and free, we found below PR which also fixes
random systemd-networkd crash:

https://github.com/systemd/systemd/pull/19631
https://github.com/systemd/systemd/issues/19629



Signed-off-by: Ranjitsinh Rathod <ranjitsinh.rathod@kpit.com>
Signed-off-by: Ranjitsinh Rathod <ranjitsinhrathod1991@gmail.com>
Signed-off-by: Steve Sakoman <steve@sakoman.com>