Revert "Update CHANGELOG.md for 11.7.8"

This reverts commit eccc8f05.

CHANGELOG.md

@@ -4,16 +4,7 @@ entry.
 ## 11.7.8 (2019-03-26)
-### Security (7 changes)
-
-- Disallow guest users from accessing Releases.
-- Fix PDF.js vulnerability.
-- Hide "related branches" when user does not have permission.
-- Fix XSS in resolve conflicts form.
-- Added rake task for removing EXIF data from existing uploads.
-- Disallow updating namespace when updating a project.
-- Use UntrustedRegexp for matching refs policy.
-
+- Unreleased due to QA failure.
 ## 11.7.7 (2019-03-19)

changelogs/unreleased/disallow-guests-to-access-releases.yml

+---
+title: Disallow guest users from accessing Releases
+merge_request:
+author:
+type: security

changelogs/unreleased/security-55503-fix-pdf-js-vulnerability.yml

+---
+title: Fix PDF.js vulnerability
+merge_request:
+author:
+type: security

changelogs/unreleased/security-56224.yml

+---
+title: Hide "related branches" when user does not have permission
+merge_request:
+author:
+type: security

changelogs/unreleased/security-56927-xss-resolve-conflicts-branch-name.yml

+---
+title: Fix XSS in resolve conflicts form
+merge_request:
+author:
+type: security

changelogs/unreleased/security-exif-migration.yml

+---
+title: Added rake task for removing EXIF data from existing uploads.
+merge_request:
+author:
+type: security

changelogs/unreleased/security-mass-assignment-on-project-update.yml

+---
+title: Disallow updating namespace when updating a project
+merge_request:
+author:
+type: security

changelogs/unreleased/use-untrusted-regexp.yml

+---
+title: Use UntrustedRegexp for matching refs policy
+merge_request:
+author:
+type: security