Fix codegen compiler error with 8.3 merge

This closes #858

src/backend/codegen/exec_variable_list_codegen.cc

@@ -466,7 +466,8 @@ bool ExecVariableListCodegen::GenerateExecVariableList(
       irb->SetInsertPoint(is_not_null_block);
     }  // End of if ( !thisatt->attnotnull )
 
-    off = att_align(off, thisatt->attalign);
+    // TODO : hardikar & nikos verify compatibility with 8.3 merge
+    off = att_align_nominal(off, thisatt->attalign);
 
     // values[attnum] = fetchatt(thisatt, tp + off) {{{
     llvm::Value* llvm_next_t_data_ptr =