dogtaginstance.py: add --debug to pkispawn

Since commits:
https://github.com/dogtagpki/pki/commit/0102d836f4eac0fcea0adddb4c98d5ea05e4e8f6
https://github.com/dogtagpki/pki/commit/de217557a642d799b1c4c390efa55493707c738e
pkispawn will not honor the pki_log_level configuration item.
All 10.9 Dogtag versions have these commits.
This affects FreeIPA in that it makes debugging Dogtag installation issues next
to impossible.
Adding --debug to the pkispawn CLI is required to revert to the previous
behavior.

Fixes: https://pagure.io/freeipa/issue/8503
Signed-off-by: François Cami <fcami@redhat.com>
Reviewed-By: Thomas Woerner <twoerner@redhat.com>
Reviewed-By: Christian Heimes <cheimes@redhat.com>
Reviewed-By: Rob Crittenden <rcritten@redhat.com>

ipaserver/install/dogtaginstance.py

@@ -190,7 +190,8 @@ class DogtagInstance(service.Service):
         subsystem = self.subsystem
         args = [paths.PKISPAWN,
                 "-s", subsystem,
-                "-f", cfg_file]
+                "-f", cfg_file,
+                "--debug"]
 
         with open(cfg_file) as f:
             logger.debug(