openvpn: Completely uninstall app

Remove /etc/openvpn when the app is uninstalled

* Tests:
1. Uninstall app and manually check if /etc/openvpn gets removed
2. Sucessfully install app
3. Functional tests: passed
4. In case we choose to purge packages in the future: I checked purging openvpn and it will not
remove /etc/openvpn.

Signed-off-by: nbenedek <contact@nbenedek.me>
[sunil: Update docstrings]
Signed-off-by: Sunil Mohan Adapa <sunil@medhas.org>
Reviewed-by: Sunil Mohan Adapa <sunil@medhas.org>

plinth/modules/openvpn/__init__.py

@@ -91,3 +91,8 @@ class OpenVPNApp(app_module.App):
         super().setup(old_version)
         privileged.setup()
         self.enable()
+
+    def uninstall(self):
+        """De-configure and uninstall the app."""
+        super().uninstall()
+        privileged.uninstall()

plinth/modules/openvpn/privileged.py

@@ -2,6 +2,7 @@
 """Configure OpenVPN server."""
 
 import os
+import shutil
 import subprocess
 
 import augeas
@@ -222,3 +223,9 @@ def load_augeas():
     aug.set('/augeas/load/Simplevars/incl[last() + 1]', ATTR_FILE)
     aug.load()
     return aug
+
+
+@privileged
+def uninstall():
+    """Remove configuration directory for OpenVPN."""
+    shutil.rmtree('/etc/openvpn', ignore_errors=True)