added httpd_user and shibd_user definitions

data/Debian.yaml

 # data/Debian.yaml
 # generic defaults for Debian-based systems
 ---
+shib_sp::shibd_user: _shibd
 shib_sp::shibd_group: _shibd
+shib_sp::httpd_user: www-data
 shib_sp::httpd_group: www-data
 

data/common.yaml

@@ -2,11 +2,9 @@
 # common defaults
 ---
 shib_sp::shib_dir: /etc/shibboleth
-shib_sp::shibd_group:
+shib_sp::shibd_user: nobody
+shib_sp::shibd_group: nogroup
 shib_sp::apache_service_enable: true
 shib_sp::apache_service_ensure: false
-shib_sp::httpd_group:
-shib_sp::entity_id: https://example.stanford.edu/
-shib_sp::support_email: support@example.com
-shib_sp::idp: https://idp.stanford.edu/
-shib_sp::metadata_uri: https://idp.stanford.edu/idp/shibboleth
+shib_sp::httpd_user: nobody
+shib_sp::httpd_group: nogroup