Catch and log on-the-fly indexing errors instead of crashing.
Review Request #11596 — Created April 13, 2021 and submitted
When failing to communicate with a search backend, operations that
would modify the search index would lead to a crash. The backend would
raise an exception, which never got caught anywhere. That could break
all manner of operations.
This change sandboxes any errors, logging the error messages when they
occur and preventing them from bubbling up.
Unit tests pass.