Fix RuboCop offense Style/RedundantSelfAssignment (#40412).

git-svn-id: https://svn.redmine.org/redmine/trunk@22826 e93f8b46-1217-0410-a6f0-8f06a7374b81

app/models/issue_query.rb

@@ -552,7 +552,7 @@ class IssueQuery < Query
   def sql_for_watcher_id_field(field, operator, value)
     db_table = Watcher.table_name
     me_ids = [0, User.current.id]
-    me_ids = me_ids.concat(User.current.groups.pluck(:id))
+    me_ids.concat(User.current.groups.pluck(:id))
     me, others = value.partition {|id| me_ids.include?(id.to_i)}
     sql =
       if others.any?