zoph, wordpress: Add conflicts on libpam-tmpdir

Closes: #2239.

- Adding Conflicts in freedombox Debian package seems to cause
unattended-upgrade to not upgrade the package to next version. This approach
seems be an alternative.

Tests:

- Install libpam-tmpdir. Go to Zoph page, see that conflicts messages is shown.
Install succeeds. libpam-tmpdir is removed.

- Install libpam-tmpdir. Go to WordPress page, see that conflicts messages is
shown. Install succeeds. libpam-tmpdir is removed.

- Remove libpam-tmpdir. Go to Zoph page, see that conflicts message is not
shown. Install succeeds.

- Remove libpam-tmpdir. Go to WordPress page, see that conflicts message is not
shown. Install succeeds.

Signed-off-by: Sunil Mohan Adapa <sunil@medhas.org>
Reviewed-by: James Valleroy <jvalleroy@mailbox.org>

plinth/modules/wordpress/__init__.py

@@ -81,7 +81,9 @@ class WordPressApp(app_module.App):
                 'php-zip',
                 # WordPress only supports MySQL/MariaDB as DB
                 'default-mysql-server',
-            ])
+            ],
+            conflicts=['libpam-tmpdir'],
+            conflicts_action=Packages.ConflictsAction.REMOVE)
         self.add(packages)
 
         firewall = Firewall('firewall-wordpress', info.name,

plinth/modules/zoph/__init__.py

@@ -67,7 +67,9 @@ class ZophApp(app_module.App):
                                       login_required=True)
         self.add(shortcut)
 
-        packages = Packages('packages-zoph', ['zoph'])
+        packages = Packages('packages-zoph', ['zoph'],
+                            conflicts=['libpam-tmpdir'],
+                            conflicts_action=Packages.ConflictsAction.REMOVE)
         self.add(packages)
 
         firewall = Firewall('firewall-zoph', info.name,