Rename `Jobs::RecoverPostUploads` to rerun the job.

Running a migration to destroy the onceoff job doesn't work
because an instance running the old code may execute the job.

app/jobs/onceoff/recover_post_uploads.rb

@@ -1,7 +1,7 @@
 require_dependency "upload_recovery"
 
 module Jobs
-  class RecoverPostUploads < Jobs::Onceoff
+  class PostUploadsRecovery < Jobs::Onceoff
     MIN_PERIOD = 30
     MAX_PERIOD = 120
 

db/migrate/20180919041529_remove_recover_post_uploads_onceoff_log.rb

@@ -1,9 +0,0 @@
-class RemoveRecoverPostUploadsOnceoffLog < ActiveRecord::Migration[5.2]
-  def up
-    DB.exec("DELETE FROM onceoff_logs WHERE job_name = 'RecoverPostUploads'")
-  end
-
-  def down
-    raise ActiveRecord::IrreversibleMigration
-  end
-end