Remove redundant scopes

These scopes were already defined by the `enum :task` method.

app/models/poll/shift.rb

@@ -10,8 +10,6 @@ class Poll
 
     enum task: { vote_collection: 0, recount_scrutiny: 1 }
 
-    scope :vote_collection,  -> { where(task: "vote_collection") }
-    scope :recount_scrutiny, -> { where(task: "recount_scrutiny") }
     scope :current, -> { where(date: Date.current) }
 
     before_create :persist_data