daemon/utils: Finish OstreeAsyncProgress after pull

Otherwise, the object might still own an idle source on the main
context, which will cause issues if another pull operation happens
again. This wasn't causing issues before because in places where we did
do multiple pull operations, we would reuse the same
`OstreeAsyncProgress` object, and the second pull operation *did* do
`ostree_async_progress_finish()`. But that's no longer the case now with
66761916.

Closes: #1676
Approved by: cgwalters

src/daemon/rpmostreed-utils.c

@@ -307,6 +307,9 @@ rpmostreed_repo_pull_ancestry (OstreeRepo               *repo,
                                               g_variant_dict_end (&options),
                                               progress, cancellable, error))
             goto out;
+
+          if (progress)
+            ostree_async_progress_finish (progress);
         }
 
       /* First pass only.  Now we can resolve the ref to a checksum. */