update_engine: remove unused variable

Count is never used in this function.

Test: th
Change-Id: I4987f0268e560eb1a7f5fa9ba9446603dcbf7193
diff --git a/payload_consumer/vabc_partition_writer.cc b/payload_consumer/vabc_partition_writer.cc
index 1a7a049..97de934 100644
--- a/payload_consumer/vabc_partition_writer.cc
+++ b/payload_consumer/vabc_partition_writer.cc
@@ -344,7 +344,7 @@
   // Setup the ExtentWriter stack based on the operation type.
   std::unique_ptr<ExtentWriter> writer = CreateBaseExtentWriter();
 
-  return executor_.ExecuteReplaceOperation(op, std::move(writer), data, count);
+  return executor_.ExecuteReplaceOperation(op, std::move(writer), data);
 }
 
 bool VABCPartitionWriter::PerformDiffOperation(