Merge branch 'sh-fix-failing-rc1-backup-spec' into 'master'

Fix failing backup filename spec for RCs

See merge request !11318

spec/tasks/gitlab/backup_rake_spec.rb

@@ -352,7 +352,7 @@ describe 'gitlab:app namespace rake task' do
     end
     it 'name has human readable time' do
-      expect(@backup_tar).to match(/\d+_\d{4}_\d{2}_\d{2}_\d+\.\d+\.\d+(-pre)?_gitlab_backup.tar$/)
+      expect(@backup_tar).to match(/\d+_\d{4}_\d{2}_\d{2}_\d+\.\d+\.\d+(-pre|-rc\d+)?_gitlab_backup.tar$/)
     end
   end
 end # gitlab:app namespace