Unwanted LOG during recovery of DROP TABLESPACE REDO

I found and fixed a bug that causes recovery (crash recovery , PITR) to throw unwanted LOG message if the tablespace symlink is not found during the processing of DROP TABLESPACE redo.
LOG: could not remove symbolic link "pg_tblspc/16384": No such file or directory

To Reproduce the issue:

1. Start the server.

2. Create a tablespace.

3. Perform Checkpoint.

4. Drop tablespace.

5. Stop server using immediate mode.

6. Start server : At this stage, recovery throw log message as mentioned above.

Reason is that DROP TABLESPACE has already removed symlink and again it is being tried to remove during recovery.
As it is very much possible that DROP TABLESPACE was successful and cleaned up the file before server crashed. So this should be considered as valid scenario and no need to throw
any LOG in such case. In case of processing of CREATE TABLESPACE redo, same is already handled.

I will add this to 2014-08 CF for review.

Thanks and Regards,
Kumar Rajeev Rastogi