[EUWE] Do not store ar object for old refresh

[Ladas]

A not clean cherry-pick of #13594

Storing AR object around is causing memory bloat. While
doing .reload on AR object is decreasing the memory bloat,
it is adding a processing time, cause .reload does a SQL query
per each object then.

Therefore removing the AR object is decreasing memory required
as well as the processing time.

Implements:
https://www.pivotaltracker.com/story/show/137741549

[Ladas]

@Fryguy could you review also this one? there are stats in the upstream PR #13594

[simaishi]

@Ladas can you resolve the conflict?

[agrare]

@simaishi is the result of #14542
Take what is in HEAD

<<<<<<< HEAD
    # Lets first index the hashes based on keys, so we can do O(1) lookups
    record_index = records.index_by { |record| build_index_from_record(keys, record) }
    record_class = records.first.class.base_class

    hashes.each do |hash|
      record = record_index[build_index_from_hash(keys, hash, record_class)]
      hash[:id] = record.id
=======
    hashes.each do |h| 
      r = records.detect { |r| keys.all? { |k| r.send(k) == r.class.type_for_attribute(k.to_s).cast(h[k]) } } 
      h[:id] = r.id
>>>>>>> Do not store ActiveRecord object anywhere in saving code.

[miq-bot]

Checked commits Ladas/manageiq@e651717~...8307f2a with ruby 2.2.6, rubocop 0.47.1, and haml-lint 0.20.0
5 files checked, 1 offense detected

app/models/ems_refresh/save_inventory_network.rb

• ❗ - Line 409, Col 43 - Rails/SkipsModelValidations - Avoid using update_all because it skips validations.