[Patch] remove duplicated smgrclose

I think there may be some duplicated codes. 

Function smgrDoPendingDeletes() calls both smgrdounlinkall() and smgrclose().
But both functions would close SMgrRelation object, it's dupliacted behavior? 

So I make this patch. Could someone take a look at it? 

Thanks for your help,

Steven 

From Highgo.com