Allow to continue to cleanup search index even if there is invalid design document

[jiangphcn]

Overview

In some situation where design document for search index created by customer is not valid, the _search_cleanup endpoint will stop to clean up. This will leave some search index orphan. The change is to allow to continue to clean up search index even if there is invalid design document for search.

Testing recommendations

make elixir tests=src/dreyfus/test/elixir/test/search_test.exs

SearchTest
  * test clean up search index with invalid design document (55.1ms)

ReshardHelpers

PartitionHelpers


Finished in 0.07 seconds
1 test, 0 failures

Related Issues or Pull Requests

Checklist

• Code is written and works correctly
• Changes are covered by tests
• Any new configurable parameters are documented in rel/overlay/etc/default.ini
• A PR for documentation changes has been made in https://github.com/apache/couchdb-documentation

[wohali]

When this is ready, please backport to 3.x.

This will be the last change before I cut CouchDB 3.1.1, if it makes it in today or tomorrow 😉

[jiangphcn]

thanks @garrensmith for review and thanks @wohali for sharing the chance to put this into 3.x. I just merged change #3119 to 3.x.