Reported by Rumen:

TASK: [fail FAIL] *************************************************************
skipping: [hostname.com]
failed: [hostname.com] => {"failed": true}
msg: Failed as requested from task
Traceback (most recent call last):
  File "/usr/local/bin/ansible-playbook", line 268, in <module>
    sys.exit(main(sys.argv[1:]))
  File "/usr/local/bin/ansible-playbook", line 208, in main
    pb.run()
  File "/Library/Python/2.7/site-packages/ansible/playbook/__init__.py", line 262, in run
    if not self._run_play(play):
  File "/Library/Python/2.7/site-packages/ansible/playbook/__init__.py", line 580, in _run_play
    if (hosts_count - len(host_list)) > int((play.max_fail_pct)/100.0 * hosts_count):
TypeError: object of type 'NoneType' has no len()

Also some minor cleanup of some fb* variables and functions, which
were remnants of the old fireball2 name

Fixes #4021

Merge branch 'devel-duplicates2' of https://github.com/smoothify/ansible into smoothify-devel-duplicates2

Merge branch 'doublecallback' of https://github.com/sergevanginderachter/ansible into sergevanginderachter-doublecallback

Merge branch 'devel-duplicates' of https://github.com/smoothify/ansible into smoothify-devel-duplicates

The play was just checking for the presence of the keyword in the
YAML datastructure, and not the value of the field, so doing something
like variable substitution was always causing the play to be accelerated

* also minor tweak to the # of retries in the connection attempt

Fixes #4012

Fixes #3943

Fixes #3556

Conflicts:
	lib/ansible/playbook/__init__.py
	lib/ansible/playbook/play.py

fix JSON extra vars quotation.

Loading the default variables in _build_role_dependencies() lead to
a side-effect where those variables were over-riding inventory variables.

* Default variables are now fed directly into roles, just like the
  other variables, so that roles see their unique values rather
  than those set at the global level.

* Role dependency duplicates are now determined by checking the params used
  when specifying them as dependencies rather than just on the name of the
  role. For example, the following would be included twice without having
  to specify "allow_duplicates: true":

  dependencies:
  - { role: foo, x: 1 }
  - { role: foo, x: 2 }

Adding regions_exclude parameter to be able to do subtractive region exc...

adding regions_exclude parameter to be able to do subtractive region exclusion. Defaults to us-gov-west-1 so as to not cause errors for people who don't have govcloud credentials but get it in their regions list

This reverts commit 1d13ec2d.

* ssh port not being picked up, always uses default of 22
* forgot to 'import time' in the fireball2 connection plugin

Fix issue 3908. There was some ilegal operations over the sets