If for some reason you require to uninstall OSLC Connect for Jira from your Jira instance, you just need to follow the official documentation as for any other plugin.
On the removal, or expiration of the license, Collaboration Links between Jira and the OSLC Remote Application remain present in both systems. Collaboration Links from Jira to the OSLC Remote Application will no longer provide rich hovers or real-time retrieval of updates or icons. Collaboration Links from the OSLC Remote Application to Jira will have labels, and URIs, that identify the Jira Issue id, but will be no longer navigable. For Configuration Enabled projects, Collaboration Links discovery services will be no longer available. Removing Collaboration Links after uninstalling the connector is still possible, but this won't remove the remote back link on the OSLC Remote Application.
In the case Jira project administrators were using IBM Engineering Lifecycle Management global configurations, you need to ask to the IBM Link Index Provider (LDX) administrator to remove the datasource created for OSLC Connect for Jira [1]. In the case Jira project administrators were using IBM Jazz Reporting Service and/or IBM Engineering Lifecycle Optimization - Engineering Insights (ENI), you need to ask to the IBM Lifecycle Query Engine (LQE) administrator as well to remove the datasources created for OSLC Connect for Jira [1].