Respect region_name in nova_compute

Signed-off-by: Oleg Bulatov <oleg@bulatov.me>
Allow raw and script to support su
Document the `ec2` group.

This group is useful when using multiple inventory sources.
Ensure params were set in ec2_vpc before accessing them

Fixes #6763
Docker: don't send wrong parameters to client.start()

As part of being updated for the 1.10 API, a couple of parameters were passed to the docker.client.start() command that it doesn't accept. This caused the module to error out if it tried to start any Docker containers. This removes those parameters so the module works again.
Support hosts without private ip without errors

Not all Linode hosts have a private ip. This fixes an actual error that was happening because the generated list of private ips is empty when there isn't one.
Added Abiquo inventory plugin
apt_key lists all keys in uppercase

allow for a little user error
docker: send 1.10 params if docker-py is new enough version
Fix collision in random filter name by merging functionality

Merges the functionality of the original jinja2 random filter with
the one we provide.

Fixes #7113
Make sure VARS_CACHE for hosts are updated with the play vars too

Fixes #6979
Give more information when a task is empty

I made a typo in a playbook and was great by:

    ERROR: expecting dict; got: None

The issue was a single - on the last line of a playbook.
With the name of the file, I was able to see right away where the
error was.
Merge pull request #7126 from mscherer/better_error_message_empty_task

Give more information when a task is empty
update documentation to include missing option

'list' was added more recently, it was omitted from the documentation.
Possible docs error: 'path' instead of 'src'

I came to this example today (line 50), and when I tried it, I got an error:

`msg: src and dest are required for creating links`

So, I changed **path** to **src** and it worked fine. Looks like the example is wrong, since the docs say "dest" is already an alias for "path", in which case we would have 2 "path" definitions.
Merge pull request #7129 from erikaheidi/patch-1

Possible docs error: 'path' instead of 'src'
Merge pull request #7128 from stansonhealth/improve_tag_docu

update ec2_tags documentation to include missing option
Merge branch 'raw-script-su-support' of https://github.com/sivel/ansible into sivel-raw-script-su-support
Merge pull request #6985 from jimi-c/issue_6763_ec2_vpc_params

Ensure params were set in ec2_vpc before accessing them
Merge pull request #6906 from idupree/patch-1

Document the `ec2` group.