Problem
-------
When Relay log index file is locked by other process,
server is unable to do any changes to the index file.
Server treats this situation as fatal and executing
intentional abort.


Analysis & Fix
--------------
Sometimes an outsider can lock index files for temporary
viewing purpose. For eg: MEB locks
binlog.index/relaylog.index to view the content of the file.
During that small period of time, deletion/rename of the
file is not possible on some platforms(Eg: Windows) Server
should retry the delete operation for few times instead of
panicking immediately.