rename Shard#description to id

test plan:
 * make sure page views are still processed

Change-Id: I07ead6c075823c2021fdcc0cc1f1fddf70f695d0
Reviewed-on: https://gerrit.instructure.com/13810
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Jacob Fugal <jacob@instructure.com>

Author: ccutrer

app/models/page_view.rb

@@ -136,7 +136,7 @@ def self.cache_queue_name
   def self.process_cache_queue
     redis = Canvas.redis
     lock_key = 'page_view_queue_processing'
-    lock_key += ":#{Shard.current.description}" unless Shard.current.default?
+    lock_key += ":#{Shard.current.id}" unless Shard.current.default?
     lock_time = Setting.get("page_view_queue_lock_time", 15.minutes.to_s).to_i
 
     # lock other processors out until we're done. if more than lock_time

config/periodic_jobs.rb

@@ -74,7 +74,7 @@
   Delayed::Periodic.cron 'PageView.process_cache_queue', '*/1 * * * *' do
     Shard.with_each_shard do
       unless Shard.current.settings[:process_page_view_queue] == false
-        PageView.send_later_enqueue_args(:process_cache_queue, :singleton => "PageView.process_cache_queue:#{Shard.current.description}")
+        PageView.send_later_enqueue_args(:process_cache_queue, :singleton => "PageView.process_cache_queue:#{Shard.current.id}")
       end
     end
   end

lib/stubs/shard.rb

@@ -49,7 +49,7 @@ def settings
     {}
   end
 
-  def description
+  def id
     "default"
   end