Issue with wiki in search results when using ES

I believe the change made in gitlab-org/gitlab-ce!3138 need to be ported for ES.

This is causing the following spec issue: https://gitlab.com/gitlab-org/gitlab-ee/builds/884275#down-build-trace

I didn't manage to reproduce this on GitLab.com.

mentioned in merge request !285 (closed)

mentioned in merge request !286 (merged)

Status changed to closed by commit 5fcaad9d

mentioned in commit 5fcaad9d

mentioned in commit bf99f58f

Mentioned in commit 5fcaad9d