Jenkins JIRA Plugin allows users to select and use credentials with System scope

Jenkins JIRA Plugin 3.0.10 and earlier does not declare the correct (folder) scope for per-folder Jira site definitions, allowing users to select and use credentials with System scope. Jira Plugin 3.0.11 defines the appropriate folder context for credential lookup. As a side effect, existing per-folder Jira sites may lose access to already configured System-scoped credentials, as if no credential was specified in the first place.