Remove delete_account() from end of test_housekeeping_deletes_files

The block count mismatch which originally caused the account check to fail has
already been fixed by some other code change, so we don't need to delete the
account to stop it being checked any more.

test/backupstore/testbackupstore.cpp

@@ -3032,11 +3032,6 @@ bool test_housekeeping_deletes_files()
 	// teardown_test_backupstore() don't fail.
 	ExpectedRefCounts.resize(2);
 
-	// Delete the account to stop teardown_test_backupstore from checking it.
-	// TODO FIXME investigate the block count mismatch that teardown_test_backupstore
-	// catches if we don't delete the account.
-	delete_account();
-
 	TEARDOWN_TEST_BACKUPSTORE();
 }