Skip loading application settings from the database when migrations are pending

Various Rails initializers (metrics, sentry, etc) are run before migrations,
which can lead to a mismatch between app/models/application_settings.rb and
schema.

lib/gitlab/current_settings.rb

@@ -19,7 +19,7 @@ module Gitlab
           settings = ::ApplicationSetting.last
         end
 
-        settings ||= ::ApplicationSetting.create_from_defaults unless ActiveRecord::Migrator.needs_migration?
+        settings ||= ::ApplicationSetting.create_from_defaults
       end
 
       settings || in_memory_application_settings
@@ -46,7 +46,8 @@ module Gitlab
       active_db_connection = ActiveRecord::Base.connection.active? rescue false
 
       active_db_connection &&
-        ActiveRecord::Base.connection.table_exists?('application_settings')
+        ActiveRecord::Base.connection.table_exists?('application_settings') &&
+        !ActiveRecord::Migrator.needs_migration?
     rescue ActiveRecord::NoDatabaseError
       false
     end

spec/controllers/projects/merge_requests_controller_spec.rb

@@ -126,7 +126,7 @@ describe Projects::MergeRequestsController do
 
           recorded = ActiveRecord::QueryRecorder.new { go(format: :json) }
 
-          expect(recorded.count).to be_within(5).of(50)
+          expect(recorded.count).to be_within(5).of(59)
           expect(recorded.cached_count).to eq(0)
         end
       end

spec/serializers/pipeline_serializer_spec.rb

@@ -113,7 +113,7 @@ describe PipelineSerializer do
 
       it "verifies number of queries" do
         recorded = ActiveRecord::QueryRecorder.new { subject }
-        expect(recorded.count).to be_within(1).of(58)
+        expect(recorded.count).to be_within(1).of(60)
         expect(recorded.cached_count).to eq(0)
       end