Deallocate storage when the tests teardown

Summary: Helps avoid lingering postgresql connections when a test fails

Test Plan: make test still works ;)

Reviewers: #reviewers!

Differential Revision: https://forge.softwareheritage.org/D322

swh/storage/tests/storage_testing.py

@@ -55,6 +55,7 @@ class StorageTestFixture:
 
     def tearDown(self):
         self.objtmp.cleanup()
+        self.storage = None
         super().tearDown()
 
     def reset_storage_tables(self):

[Phabricator Migration user]

Some references in the commit message have been migrated:

• D322 is now !75 (closed)