namespace deletion: propagate delete-groups=false but ENOTEMPTY as error

after all we couldn't delete all that got requested, ideally this
should become a task where we can log what got deleted and what
not...

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>

pbs-datastore/src/datastore.rs

@@ -487,6 +487,7 @@ impl DataStore {
                         log::debug!("namespace {ns} already removed")
                     }
                     Err(nix::Error::Sys(nix::errno::Errno::ENOTEMPTY)) if !delete_groups => {
+                        removed_all_requested = false;
                         log::debug!("skip removal of non-empty namespace {ns}")
                     }
                     Err(err) => {