disable op count overhead for v2

v2 does not use op buffer count, so this estimation overhead should only
be updated for v3

Test: th
Change-Id: Ib9ad838abd03839db390b0dbd126c1a477803eea
diff --git a/payload_generator/delta_diff_generator.cc b/payload_generator/delta_diff_generator.cc
index 426efbc..4abff92 100644
--- a/payload_generator/delta_diff_generator.cc
+++ b/payload_generator/delta_diff_generator.cc
@@ -146,7 +146,9 @@
 
     // add a 1% overhead to our estimation
     cow_info_->cow_size = cow_info_->cow_size * 1.01;
-    cow_info_->op_count_max = std::max(int(cow_info_->op_count_max), 25);
+    if (config_.target.dynamic_partition_metadata->cow_version() >= 3) {
+      cow_info_->op_count_max = std::max(int(cow_info_->op_count_max), 25);
+    }
     // ops buffer size == 0 for v2 version of cow format
     LOG(INFO) << "Estimated COW size for partition: " << new_part_.name << " "
               << cow_info_->cow_size