Reindex API
 url rest/gitplugin/1.0/index.json example: http://andrl:2990/jira/rest/gitplugin/1.0/index.json
API starts reindex process in separate thread. So response will be returned immediately. 
 methodGET  
 parameters  
 repoIdRepository Id (Long) Optional. If not specified all repositories will be indexed
 threadId Id of thread to track (Long)Optional. Used to track messages for particular thread. This parameter is not required to start reindex.
response  
 Example:
 {"success":true,"finished":true,"threadId":172,"messages":{"Indexing test-repo":100.0},"errors":{},"lastOperationPercent":100.0}