ActiveRecord 3.1 does not restore connection inheritance after removing a connection from a model

Gemfile

source :rubygems

gem 'activerecord', '~> 3.1.0'
gem 'sqlite3'

output.txt

$ bundle update
[...]
$ bundle exec ruby separate_conn.rb 
Creating database first.sqlite3
sqlite3 first.sqlite3 'CREATE TABLE people (id INTEGER PRIMARY KEY AUTOINCREMENT, name varchar(255) NOT NULL)'
sqlite3 first.sqlite3 "INSERT INTO people (name) VALUES ('Jo')"

Creating database second.sqlite3
sqlite3 second.sqlite3 'CREATE TABLE people (id INTEGER PRIMARY KEY AUTOINCREMENT, name varchar(255) NOT NULL)'
sqlite3 second.sqlite3 "INSERT INTO people (name) VALUES ('Fred')"

Connecting to first database on AR::Base
Person.all.collect(&:name): ["Jo"]

Connecting to second database on Person
Person.all.collect(&:name): ["Fred"]

Disconnecting from second database
Database connection did not revert to AR::Base's connection

separate_conn.rb

#!/usr/bin/env ruby

require 'bundler'
Bundler.setup

require 'active_record'

###### Set up databases

def sh(cmd)
  puts cmd
  system cmd
end

{
  'first.sqlite3' => 'Jo',
  'second.sqlite3' => 'Fred'
}.each do |db, name|
  puts "Creating database #{db}"
  FileUtils.rm_rf db
  sh("sqlite3 #{db} 'CREATE TABLE people (id INTEGER PRIMARY KEY AUTOINCREMENT, name varchar(255) NOT NULL)'")
  sh("sqlite3 #{db} \"INSERT INTO people (name) VALUES ('#{name}')\"")
  puts
end

###### Models

class Person < ActiveRecord::Base; end

###### The problem:

puts "Connecting to first database on AR::Base"
ActiveRecord::Base.establish_connection :adapter => 'sqlite3', :database => 'first.sqlite3'
puts "Person.all.collect(&:name): #{Person.all.collect(&:name).inspect}"
puts
puts "Connecting to second database on Person"
Person.establish_connection :adapter => 'sqlite3', :database => 'second.sqlite3'
puts "Person.all.collect(&:name): #{Person.all.collect(&:name).inspect}"
puts
puts "Disconnecting from second database"
Person.remove_connection

begin
  puts "Person.all.collect(&:name): #{Person.all.collect(&:name).inspect}"
rescue ActiveRecord::ConnectionNotEstablished => e
  puts "Database connection did not revert to AR::Base's connection"
end

Demonstration for rails #2820. Clone, bundle update, then run separate_conn.rb to see the results.