Move private reader to private section

Author: deivid-rodriguez

bundler/lib/bundler/definition.rb

@@ -476,9 +476,6 @@ def most_specific_locked_platform
       end
     end
 
-    attr_reader :sources
-    private :sources
-
     def nothing_changed?
       return false unless lockfile_exists?
 
@@ -504,6 +501,8 @@ def unlocking?
 
     private
 
+    attr_reader :sources
+
     def should_add_extra_platforms?
       !lockfile_exists? && generic_local_platform_is_ruby? && !Bundler.settings[:force_ruby_platform]
     end