[freeipa PR#3672][opened] Make sure to have storage space for tag

[simo5]

   URL: https://github.com/freeipa/freeipa/pull/3672
Author: simo5
 Title: #3672: Make sure to have storage space for tag
Action: opened

PR body:
"""
ber_scanf expects a pointer to a ber_tag_t to return the tag pointed at
by "t", if that is not provided the pointer will be store in whatever
memory location is pointed by the stack at that time causeing a crash.

Note that this is effectively unused code because in ipa-kdb the only
party that can write a key_data structure to be stored is te kdb_driver
itself and we never encode these s2kparam data.

But we need to handle this for future proofing.

Fixes #8071
"""

To pull the PR as Git branch:
git remote add ghfreeipa https://github.com/freeipa/freeipa
git fetch ghfreeipa pull/3672/head:pr3672
git checkout pr3672