Cleanup - Removed unused function parameter in reorder buffer & parallel vacuum

Hi,

While checking through the code I found that  some of the function
parameters in reorderbuffer & vacuumlazy are not used. I felt this
could be removed. I'm not sure if it is kept for future use or not.
Attached patch contains the changes for the same.
Thoughts?

Regards,
Vignesh
EnterpriseDB: http://www.enterprisedb.com