[rubygems/rubygems] Remove unused default value

ruby/rubygems@e9f4d1e5c2

Author: deivid-rodriguez

lib/bundler/definition.rb

@@ -833,7 +833,7 @@ def specs_changed?(source)
       !locked || dependencies_for_source_changed?(source, locked) || specs_for_source_changed?(source)
     end
 
-    def dependencies_for_source_changed?(source, locked_source = source)
+    def dependencies_for_source_changed?(source, locked_source)
       deps_for_source = @dependencies.select {|s| s.source == source }
       locked_deps_for_source = locked_dependencies.select {|dep| dep.source == locked_source }