undercloud/upgrade: change ownership for ironic-dbsync.log

A change was done in puppet-ironic:
https://review.openstack.org/#/c/457478/

It broke TripleO upgrades because ironic-dbsync.log used to be owned by
root:root and now it's managed by ironic user in puppet-ironic, which is
good.

Because we want to support existing deployments, we need a way to handle
the new owership change, so let's do it in a upgrade task in
undercloud.py. Puppet will be able to run ironic-dbsync and we'll remove
this workaround after Pike release.

Newton backport note:
  Since the Newton version does not have "upgrade" flag passed to install,
  a try..except block was added to handle fresh installations, where
  the affected file does not exist.

Co-Authored-By: Dmitry Tantsur <dtantsur@redhat.com>
Change-Id: I325c30f49b765ef6413743491902e97735877321
(cherry picked from commit 4077ec823c)

instack_undercloud/undercloud.py

@@ -1238,6 +1238,18 @@ def install(instack_root):
     _validate_configuration()
     instack_env = _generate_environment(instack_root)
     _generate_init_data(instack_env)
+    # Even if we backport https://review.openstack.org/#/c/457478/
+    # into stable branches of puppet-ironic, we still need a way
+    # to handle existing deployments.
+    # This task will fix ironic-dbsync.log ownership on existing
+    # deployments during an upgrade. It can be removed after we
+    # release Pike.
+    try:
+        _run_command(['sudo', '/usr/bin/chown', 'ironic:ironic',
+                      '/var/log/ironic/ironic-dbsync.log'])
+    except subprocess.CalledProcessError:
+        # assume it's a fresh installation, and the file does not exist
+        pass
     _die_tuskar_die()
     _run_yum_update(instack_env)
     _run_instack(instack_env)

releasenotes/notes/ironic-dbsync-da5d047e92841f78.yaml

@@ -0,0 +1,9 @@
+---
+upgrade:
+  - |
+    Undercloud upgrade will handle the change of ownership for ironic-dbsync.log
+    to become ironic:ironic instead of root:root.
+    Indeed, https://review.openstack.org/#/c/457478/ broke TripleO upgrades but
+    it's to fix a valid issue in the puppet-ironic module. We still want to handle
+    upgrades for existing deployments, that's why we manage the ownership change
+    in instack-undercloud.