Fixed shebang in module example

Fixes #6653

Add tests for rax_scaling_group

Fix docs typo

Fixes #5779

Change syslog (priority) level from LOG_NOTICE to LOG_INFO

If you look at the meaning of the different syslog levels, NOTICE means that the event may need someone to look at it. Whereas INFO is pure informational.

Since module invocations are in fact requested (deliberate) actions, they shouldn't need any additional post-processing, and therefore should not be logged as NOTICE.

This may seem like hairsplitting, but correctly categorizing system events helps weeding through the noise downhill.

According to Wikipedia: https://en.wikipedia.org/wiki/Syslog

5 	Notice 		notice 	Events that are unusual but not error conditions .
6 	Informational 	info 		Normal operational messages -no action required. Example an application has started, paused or ended successfully.

implemneted become handling here, cannot generalize well enough in base class

Fixes #5375

Fixes #5764

* fixed a bug in which failures from a with_* loop were not being
  caught correctly, leading to tasks continuing when they should stop
* when ignore_errors is enabled, the failure will no longer count
  towards the number of failed tasks