Explicitly close status database

Using `__del__` often closes the database on a different thread, which
is not supported by the sqlite module and produces a different warning.

Explicitly close the status database everywhere it is used.

tests/unit/sync/test_status.py

@@ -34,3 +34,5 @@ def test_legacy_status(status_dict):
         assert meta2_a.to_status() == meta_a
         assert meta2_b.to_status() == meta_b
         assert ident_a == ident_b == ident
+
+    status.close()

tests/unit/sync/test_sync.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import asyncio
+import contextlib
 from copy import deepcopy
 
 import aiostream
@@ -25,13 +26,12 @@ from vdirsyncer.sync.status import SqliteStatus
 from vdirsyncer.vobject import Item
 
 
-async def sync(a, b, status, *args, **kwargs):
-    new_status = SqliteStatus(":memory:")
-    new_status.load_legacy_status(status)
-    rv = await _sync(a, b, new_status, *args, **kwargs)
-    status.clear()
-    status.update(new_status.to_legacy_status())
-    return rv
+async def sync(a, b, status, *args, **kwargs) -> None:
+    with contextlib.closing(SqliteStatus(":memory:")) as new_status:
+        new_status.load_legacy_status(status)
+        await _sync(a, b, new_status, *args, **kwargs)
+        status.clear()
+        status.update(new_status.to_legacy_status())
 
 
 def empty_storage(x):

vdirsyncer/cli/utils.py

@@ -232,7 +232,8 @@ def manage_sync_status(base_path: str, pair_name: str, collection_name: str):
         prepare_status_path(path)
         status = SqliteStatus(path)
 
-    yield status
+    with contextlib.closing(status):
+        yield status
 
 
 def save_status(

vdirsyncer/sync/status.py

@@ -174,9 +174,6 @@ class SqliteStatus(_StatusBase):
             self._c.close()
             self._c = None
 
-    def __del__(self):
-        self.close()
-
     def _is_latest_version(self):
         try:
             return bool(