lib/installation: Don't stop getting removable remotes if one attempt fails

When listing the removable remotes, it will stop the operation after the
first configurable remote that has no collection ID set.
This is of course a problem as such an occurrence is not a reason for
not trying to list any remaining remotes.

This patch fixes that by simply reporting the failures as a debug
message instead of aborting.

Closes: #1587
Approved by: mwleeds

lib/flatpak-installation.c

@@ -1198,6 +1198,7 @@ flatpak_installation_list_remotes_by_type (FlatpakInstallation     *self,
 
   for (i = 0; remote_names[i] != NULL; ++i)
     {
+      g_autoptr(GError) local_error = NULL;
       if (types_filter[FLATPAK_REMOTE_TYPE_STATIC])
         g_ptr_array_add (remotes, flatpak_remote_new_with_dir (remote_names[i],
                                                                dir_clone));
@@ -1205,8 +1206,9 @@ flatpak_installation_list_remotes_by_type (FlatpakInstallation     *self,
       /* Add the dynamic mirrors of this remote. */
       if (!list_remotes_for_configured_remote (self, remote_names[i], dir_clone,
                                                types_filter, remotes,
-                                               cancellable, error))
-        return NULL;
+                                               cancellable, &local_error))
+        g_debug ("Couldn't find remotes for configured remote %s: %s",
+                 remote_names[i], local_error->message);
     }
 
   return g_steal_pointer (&remotes);