* Foreman: Make the foreman callback more defensive
This ensures the ssl_verify attribute is always set. It also handles
None in _disable_plugin.
* Foreman: Handle ints in verify_certs
The default value for verify_certs is 1 which is an int. That has no
lower() function. By casting it to a str we can handle it later in
_ssl_verify().
* Foreman: Clean up coding style
* Foreman: Use get_option in favor of _plugin_options