docker::run turns underscores in the $title and $depends_array variables into dashes

[lorijean44]

The docker::run type tries to sanitize the title and the depends variables. One of the things that gets sanitized is underscores. I ended up modifying it to not do this, as I saw no issues using underscores at all.

Here's a diff:

-  $sanitised_title = regsubst($title, '[^0-9A-Za-z.\-]', '-', 'G')
-  $sanitised_depends_array = regsubst($depends_array, '[^0-9A-Za-z.\-]', '-', 'G')
+## Turn anything that is not a Number, letter, dash, or underscore into a dash
+  $sanitised_title = regsubst($title, '[^0-9A-Za-z.\-_]', '-', 'G')
+  $sanitised_depends_array = regsubst($depends_array, '[^0-9A-Za-z.\-_]', '-', 'G')

To be fair, I did not adequately test the depends array having underscores.