Scheduled Reports stop working after on of the Jira DC nodes is shutdown

Defect

Xporter scheduled reports stop working after one of the node of a Jira DC is shutdown.

This problem only happens on Jira Datacenter platform.

Steps to reproduce:

1. Create some Scheduled reports
2. Shutdown one of the DC nodes
3. Check if the scheduled are listed on Scheduler details(System page on Jira Administration)

Cause:

Xporter is unregistering all the scheduled reports from Jira Scheduling service when the app is disabled.