Forgot to change named_scope to scope in an ArgumentError raise exception for...

Forgot to change named_scope to scope in an ArgumentError raise exception for duplication scopes related to commit d60bb0a9 [#3736 status:resolved]
Signed-off-by: NJosé Valim <jose.valim@gmail.com>

activerecord/lib/active_record/named_scope.rb

@@ -101,7 +101,7 @@ def scope(name, options = {}, &block)
         name = name.to_sym
 
         if !scopes[name] && respond_to?(name, true)
-          raise ArgumentError, "Cannot define named_scope :#{name} because #{self.name}.#{name} method already exists."
+          raise ArgumentError, "Cannot define scope :#{name} because #{self.name}.#{name} method already exists."
         end
 
         scopes[name] = lambda do |parent_scope, *args|