Remove ancient, outdated feedback url key. Unused in current code.

etc/org.opencastproject.organization-mh_default_org.cfg

@@ -122,16 +122,6 @@ prop.org.opencastproject.admin.help.restdocs.url=/rest_docs.html
 # Default: undefined
 prop.org.opencastproject.admin.mediamodule.url=${prop.org.opencastproject.engage.ui.url}/engage/ui
 
-# Link to a JIRA feedback widget collector.
-#
-# If the property is specified, the feedback button in the lower right corner will
-# link to the widget and allow to create issues right inside the project. If the
-# property is not specified, the feedback button will be hidden.
-#
-# Value: <a complete url with scheme and port>
-#
-#prop.org.opencastproject.admin.feedback.url=
-
 # Flag to display imprint and privacy in admin-UIs footer
 #
 # Value: <boolean>