package/trousers: add upstream security fix

Fixes the following security issues:

CVE-2020-24332
If the tcsd daemon is started with root privileges,
the creation of the system.data file is prone to symlink attacks

CVE-2020-24330
If the tcsd daemon is started with root privileges,
it fails to drop the root gid after it is no longer needed

CVE-2020-24331
If the tcsd daemon is started with root privileges,
the tss user has read and write access to the /etc/tcsd.conf file

For details, see the advisory:
https://www.openwall.com/lists/oss-security/2020/05/20/3



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