Fix stream closing when sending file with `ActionController::Live` included.

Fixes #12381
Check `respond_to` before delegation due to: https://github.com/ruby/ruby/commit/d781caaf313b8649948c107bba277e5ad7307314
Merge branch 'master' into ruby-2.2

* master:
  Revert "ask the fixture set for the sql statements"
[ci skip] - error_messages_for has been deprecated since 2.3.8 - lets reduce any confusion for users
Restore DATABASE_URL even if it's nil in connection_handler test

- We have to restore DATABASE_URL to its previous state irrespective of
  previous value is nil or not
Merge pull request #13659 from prathamesh-sonpatki/fix-build

Restore DATABASE_URL even if it's nil in connection_handler test
Merge pull request #13657 from leriksen/master

[ci skip] - error_messages_for has been deprecated since 2.3.8 - lets re...
doc, API example on how to use `Model#exists?` with multiple IDs. [ci skip]

Refs #13658
Merge branch 'ruby-2.2'

* ruby-2.2:
  Check `respond_to` before delegation due to: https://github.com/ruby/ruby/commit/d781caaf313b8649948c107bba277e5ad7307314
Merge branch 'master' into laurocaetano-fix_send_file

* master: (536 commits)
  doc, API example on how to use `Model#exists?` with multiple IDs. [ci skip]
  Restore DATABASE_URL even if it's nil in connection_handler test
  [ci skip] - error_messages_for has been deprecated since 2.3.8 - lets reduce any confusion for users
  Ensure Active Record connection consistency
  Revert "ask the fixture set for the sql statements"
  Check `respond_to` before delegation due to: https://github.com/ruby/ruby/commit/d781caaf313b8649948c107bba277e5ad7307314
  Adding Hash#compact and Hash#compact! methods
  MySQL version 4.1 was EOL on December 31, 2009 We should at least recommend modern versions of MySQL to users.
  clear cache on body close so that cache remains during rendering
  add a more restricted codepath for templates fixes #13390
  refactor generator tests to use block form of Tempfile
  Fix typo [ci skip]
  Move finish_template as the last public method in the generator
  Minor typos fix [ci skip]
  make `change_column_null` reversible. Closes #13576.
  create/drop test and development databases only if RAILS_ENV is nil
  Revert "Speedup String#to"
  typo fix in test name. [ci skip].
  `core_ext/string/access.rb` test what we are documenting.
  Fix typo in image_tag documentation
  ...

Conflicts:
	actionpack/CHANGELOG.md
Removing without_thor_debug

a1d0c0fa3d8ca97edc8f2a1d6ba96af19221dbad

as bundler 1.5.2 is out now
Merge pull request #13671 from arunagw/upgrade-bundler

Removing without_thor_debug