[PATCH pmg-api] d/postinst: do not error out on chown/chmod /var/spool/pmg/

[Stoiko Ivanov <s.ivanov@proxmox.com>]

When /var/spool/pmg is a dedicated mountpoint on an unpriviledged
container, its `.lost+found` is not writeable by root inside the
container.

In this case - it makes sense to not cause postinst to error-out, as
the failing change of mode/ownership is not problematic.

I don't think that it's a too common setup, but as /var/spool/pmg is
one of the places which does grow with more usage (quarantined files)
having it on a separate mount-point can make sense.

I considered guarding all the changes of metadata with '|| true', but
as failing to change ownership will result in broken mail-processing
for most of the changes it seems better to fail during apt to have the
user notice the issue as early as possible.

reported in our community forum:
https://forum.proxmox.com/threads/184240/post-858302

Signed-off-by: Stoiko Ivanov <s.ivanov@proxmox.com>
---
 debian/postinst | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/debian/postinst b/debian/postinst
index ee218ab9..ce514ade 100644
--- a/debian/postinst
+++ b/debian/postinst
@@ -40,8 +40,8 @@ migrate_pmg_smtp_filter() {
 
     printf "Adjusting group ownership of the mail spool, this might take a while\n"
     # no -v: the spool can hold millions of mails
-    chgrp -R pmg /var/spool/pmg
-    chmod -R g+w /var/spool/pmg
+    chgrp -R pmg /var/spool/pmg || true
+    chmod -R g+w /var/spool/pmg || true
 
     chgrp -Rv pmg /etc/pmg/dkim
     chmod -Rv g+rX /etc/pmg/dkim
-- 
2.47.3