Conflicts:
	lib/ansible/inventory/__init__.py
	lib/ansible/modules/core
	lib/ansible/utils/__init__.py
	lib/ansible/utils/module_docs.py

limit extensions for files in group/host_vars dir

Include more info when a task fails

There is a common pattern in modules where some parameters are required
only if another parameter is present AND set to a particular value. For
instance, if a cloud server state is "present" it's important to
indicate the image to be used, but if it's "absent", the image that was
used to launch it is not necessary. Provide a check that takes as an
input a list of 3-element tuples containing parameter to depend on, the
value it should be set to, and a list of parameters which are required
if the required parameter is set to the required value.

Add required_if to AnsibleModule

Adds "playbook", "role", and "task" fields to the output when a task fails.

This makes it easier to pinpoint where the problem is, especially
when you have a lot of roles and playbooks.

e.g.:

    failed: [vagrant] => {..."playbook": "/Users/marca/dev/ansible/vagrant.yml",
                          ..."role": "pythonapp",
                          ..."task": "pip install -r /opt/src/{{ sm_app_role }}/requirements.txt"...}

Setting LC_MESSAGES: prevent unparseable messages (fixes issue #9635)

Remove duplicate RETRY_FILES_* constants

fix typo in --ask-sudo-pass reference within playbook_intro doc

only files with extensions as per
C.YAML_FILENAME_EXTENSIONS should be parsed

inventory vars: make loading from a directory obey the same rules as
when checking the base paths, looking at the file name extensions
as defined in CONSTANTS.YAML_FILENAME_EXTENSIONS

Fixes Github issue #11017

Minor Fix for broken link

The default user expected in the connection information is the current
user, not root