Security fixes:

* Strip lookup calls out of inventory variables and clean unsafe data
  returned from lookup plugins (CVE-2014-4966)
* Make sure vars don't insert extra parameters into module args and prevent
  duplicate params from superseding previous params (CVE-2014-4967)
[mount] Add documentation for fstab option
[mount] make sure fstab exists

This is mainly to prevent from failing with no such file or directory
during module execution.
Fix ec2_setup task param quoting
Merge pull request #8223 from renard/create-fstab-if-not-exists

Create fstab if not exists
Make code more PEP8 compliant (if(x))

Remove useless parentheses, `if (x):` should be `if x:`.
Make code more PEP8 compliant (whitespace)

> Always surround these binary operators with a single space on either
> side: assignment (`=`), augmented assignment (`+=`, `-=`
> etc.), comparisons (`==`, `<`, `>`, ``!=``, `<>`, `<=`,
> `>=`, `in`, `not in`, `is`, `is not`), Booleans (`and`,
> `or`, `not`).
Make docker inventory plugin more Pythonic

There's no need to check if kwargs is empty before iterating over it.
Refactor CronTab.is_empty
Make code more PEP8 compliant (if len(seq))

> For sequences, (strings, lists, tuples), use the fact that empty
> sequences are false.
>
>     Yes: if not seq:
>          if seq:
>
>     No: if len(seq)
>         if not len(seq)