The changes have been backported (to 10.5) through PR: https://github.com/dogtagpki/pki/pull/93

10_5 branch:
============
The commit that fixes this specific bug: https://github.com/dogtagpki/pki/commit/c6c6757b4c566d10d25fe220fa9f59539c7a55ee


This commit ensures that pkispawn reuses the same log dir (if exist) instead of throwing name space collision error

This bug can be verified while testing: https://bugzilla.redhat.com/show_bug.cgi?id=1372056

Verification steps provided for QE:
1. Install a subsystem using pkispawn
2. `tree /var/log/pki/` # note the tree structure
3. Run `pkidestroy -s <subsystem> -i <instance>`
4. `tree /var/log/pki/` # the tree should match #2
5. Install the subsystem again

No error should be thrown.

Also, you can do `tail -f /var/log/pki/<instance>/<subsystem>/<corresponding debug file>` while executing the above steps to see that new logs are appended to existing log files.

1. namespace collision error is not displayed when pkispawn is run.
2. Reinstall using pkispawn appends the existing log file.

Verified on RHEL7.7
[root@pki1 pki]# cat /etc/redhat-release 
Red Hat Enterprise Linux Server release 7.7 Beta (Maipo)
pki-ca-10.5.16-2.el7.noarch
pki-kra-10.5.16-2.el7.noarch
pki-base-10.5.16-2.el7.noarch
389-ds-base-1.3.9.1-8.el7.x86_64

#pkispawn -s CA -f /root/config2/ca.cfg
[root@pki1 ~]# pkidaemon status
Status for topology-01-CA: topology-01-CA is running ..

    [CA Status Definitions]
    Unsecure URL        = http://pki1.example.com:8080/ca/ee/ca
    Secure Agent URL    = https://pki1.example.com:8443/ca/agent/ca
    Secure EE URL       = https://pki1.example.com:8443/ca/ee/ca
    Secure Admin URL    = https://pki1.example.com:8443/ca/services
    PKI Console Command = pkiconsole https://pki1.example.com:8443/ca
    Tomcat Port         = 8005 (for shutdown)

[root@pki1 ~]# tree /var/log/pki/
/var/log/pki/
8 directories, 39 files

[root@pki1 ~]# pkidestroy -s CA -i topology-01-CA
Log file: /var/log/pki/pki-ca-destroy.20190612044525.log
Loading deployment configuration from /var/lib/pki/topology-01-CA/ca/registry/ca/deployment.cfg.
WARNING: The 'pki_pin' in [DEFAULT] has been deprecated. Use 'pki_server_database_password' instead.
Uninstalling CA from /var/lib/pki/topology-01-CA.
pkidestroy  : WARNING  ....... Directory '/etc/pki/topology-01-CA/alias' is either missing or is NOT a directory!
Uninstallation complete.

[root@pki1 ~]# tree /var/log/pki/
8 directories, 44 files

[root@pki1 ~]# pkispawn -s CA -f /root/config2/ca.cfg 
Log file: /var/log/pki/pki-ca-spawn.20190612044614.log
Loading deployment configuration from /root/config2/ca.cfg.
Installing CA into /var/lib/pki/topology-01-CA.
Storing deployment configuration into /etc/sysconfig/pki/tomcat/topology-01-CA/ca/deployment.cfg.
Notice: Trust flag u is set automatically if the private key is present.
    ==========================================================================
                                INSTALLATION SUMMARY
    ==========================================================================
      Administrator's username:             caadmin
      Administrator's PKCS #12 file:
            /opt/topology-01-CA/ca_admin_cert.p12
      To check the status of the subsystem:
           systemctl status pki-tomcatd
      To restart the subsystem:
           systemctl restart pki-tomcatd
      The URL for the subsystem is:
            https://pki1.example.com:8443/ca
      PKI instances will be enabled upon system boot

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2019:2228