Fix new_constants_selector method name.

Author: calavera

lib/cc/formatters/snapshot_formatter.rb

@@ -63,7 +63,7 @@ def initialize(repo, payload)
 
     private
 
-      def new_constant_selector
+      def new_constants_selector
         Proc.new { |constant| to_rating(constant) < C }
       end
 
@@ -91,7 +91,7 @@ def from_rating(constant)
     # Override the base snapshot formatter for be more lax grouping information.
     # This is useful to show more information for testing the service.
     class Sample < Base
-      def new_constant_selector
+      def new_constants_selector
         Proc.new { |_| true }
       end