Return a friendly error message if aptitude isn't installed

Add documentation for Role Variables to the Best Practices page

openbsd_pkg corner case fixes

apt_repository: enhance documentation

Minor typo on site about host_key_checking config section.

Create with_items example with a registered var

Update to conventional task format

mysql_db small fix to docs

Bail out if the SSH command fails rather than continuing with an
empty tmp variable.

add documentation for with_nested

Update error message since user may have specified connection type via non command line or by default.

Allow roles to be interpolated from --extra-vars

Check for existence of isatty on stdout before calling it

fatal if target selinux and missing bindings

(git module) Resolve incompatability between depth and version

Fix for  Issue #3586:  UnboundedLocalError when removing a logical volume.

Signed-off-by: Brian Coca <briancoca+dev@gmail.com>

attempted w/o selinux python bindings
Signed-off-by: Brian Coca <briancoca+dev@gmail.com>

Git is unable to checkout the specified `version` when the repository is
cloned with a reduced history (`depth`).  However, if the repository is
already cloned, subsequent git module calls will update the repository
(default update=True), then properly checkout the specified `version`.
To allow the initial call to properly clone the specified `version`, at
the specified `depth`, this patch adds the `--branch` parameter when
cloning the repository.