[rubygems/rubygems] rename Index#== to Index#subset?

https://github.com/rubygems/rubygems/commit/a96a561087

lib/bundler/definition.rb

@@ -657,8 +657,7 @@ module Bundler
       locked_index = Index.new
       locked_index.use(@locked_specs.select {|s| source.can_lock?(s) })
 
-      # order here matters, since Index#== is checking source.specs.include?(locked_index)
-      locked_index != source.specs
+      !locked_index.subset?(source.specs)
     rescue PathError, GitError => e
       Bundler.ui.debug "Assuming that #{source} has not changed since fetching its specs errored (#{e})"
       false

lib/bundler/index.rb

@@ -145,8 +145,7 @@ module Bundler
     end
 
     # Whether all the specs in self are in other
-    # TODO: rename to #include?
-    def ==(other)
+    def subset?(other)
       all? do |spec|
         other_spec = other[spec].first
         other_spec && dependencies_eql?(spec, other_spec) && spec.source == other_spec.source