Merge branch 'gitaly-repo-squash-in-progress-opt-out' into 'master'

Make Repo#squash_in_progress Opt-Out

See merge request gitlab-org/gitlab-ce!19088

lib/gitlab/git/repository.rb

@@ -1334,7 +1334,7 @@ module Gitlab
       end
 
       def squash_in_progress?(squash_id)
-        gitaly_migrate(:squash_in_progress) do |is_enabled|
+        gitaly_migrate(:squash_in_progress, status: Gitlab::GitalyClient::MigrationStatus::OPT_OUT) do |is_enabled|
           if is_enabled
             gitaly_repository_client.squash_in_progress?(squash_id)
           else