concurrent-ruby is not present in 4.2

Since bundler 1.12.0, the gemspec is validated so the `bundle install`
command will fail just after the gem is created causing confusion to the
users. This change was a bug fix to correctly validate gemspecs.

Backport #25364 to 4-2-stable

Backport 3055f59e

Do not inspect array of over 10 elements

Currently `Type::Date#serialize` does not cast a value to a date object.
It should be cast to a date object for finding by date column correctly
working.

Fixes #25354.

Update changelog for backport of ActiveSupport::Logger.broadcast #silence and ActiveSupport::LoggerThreadSafeLevel

Adds whitespace for consistency

There are 11 references to index: true in this file and 10 of them have
space between "index" and "true".  This just makes the 11th one
consistent.

Fix jobs overriding AJ::Base#logger

Backport to 4.2: Broadcast #silence on ActiveSupport::Logger

Check that we are not hitting Kernel#capture aliased to #silence in the reporting patches. Deprecated and removed in 5.

Fixes #25391

Backport ActiveSupport::LoggerThreadSafeLevel

Fix #23609

Commit 629efb60 introduced thread safety to logger silencing but it
didn't take into account the fact that the logger can be extended with
broadcasting to other logger.

This commit introduces local_level to broadcasting Module which enables
broadcasted loggers to be properly silenced.

Conflicts:
	activesupport/lib/active_support/logger_silence.rb

This behavior was broken by 36e9be85. When the value is assigned
directly, either through mass assignment or directly assigning a hash,
the hash gets passed through to this writer method directly. While this
is intended to handle certain cases, when an explicit converter has been
provided, we should continue to use that instead. The positioning of the
added guard caused the new behavior to override that case.

Fixes #25210

Removing constant works diferently in Ruby 1.9

This reverts commit bd449674.

Reason: tests are broken after this change.

Execute default_scope defined by abstract class within the scope of subclass

* Hash#from_xml works with frozen strings

Fixes #24647

* Fix rexml engine test

[Marek Kirejczyk + Rafael Mendonça França]

Fixes Inflector#titleize to work with SafeBuffer

Fix release year of v4.2.5.1 [ci skip]

Make 'migrate' clear the schema cache afterward

Without clearing the caches afterward, removals done in migrations would
not be reflected in a separate task in the same process. That is, given
a table with a migration to remove a column, the schema cache would
still reflect that a table has that in something such as the
'db:seed' task:

`rake db:migrate db:seed`
(A common thing to do in a script for a project ala `bin/setup`)

vs

`rake db:migrate && rake db:seed`
(Two processes)

The first would not reflect that the column was removed.
The second would (cache reset).

Backport #21950

Fix generated projection fields in group by query

Closes #21922

Let `Book(id, author_id)`, `Photo(id, book_id, author_id)` and `Author(id)`

Running `Book.group(:author_id).joins(:photos).count` will produce:

* Rails 4.2 - conflicts `author_id` in both projection and group by:
```sql
SELECT COUNT(*) AS count_all, author_id AS author_id
  FROM "books" INNER JOIN "photos" ON "photos"."book_id" = "books"."id"
 GROUP BY author_id
```

* Master (9d02a25d) - conflicts `author_id` only in projection:
```sql
SELECT COUNT(*) AS count_all, author_id AS author_id
  FROM "books" INNER JOIN "photos" ON "photos"."book_id" = "books"."id"
 GROUP BY "books"."author_id"
```

* With this fix:
```sql
SELECT COUNT(*) AS count_all, "books"."author_id" AS books_author_id
  FROM "books" INNER JOIN "photos" ON "photos"."book_id" = "books"."id"
 GROUP BY "books"."author_id"
```

This can be an issue when TZInfo::TimeZone#current_period is refreshed
due to timezone period transition, but it's not reflected in
ActiveSupport::TimeZone object.

For example, on Sun, 26 Oct 2014 22:00 UTC, Moscow changed its TZ from
MSK +04:00 to MSK +03:00 (-1 hour). If ActiveSupport::TimeZone['Moscow']
happens to be initialized just before the timezone transition, it will
cache its stale utc_offset even after the timezone transition.

This commit removes cache and fixes this issue.
Signed-off-by: NJeremy Daer <jeremydaer@gmail.com>