Fix one liner

Ensuring that the expression is evaluated before being outputed. In
response to comment from aosp/2708333

Test: th
Change-Id: I073c143f1c4e32af11e235ce782947b250117dc5
diff --git a/fs_mgr/libsnapshot/libsnapshot_cow/writer_v2.cpp b/fs_mgr/libsnapshot/libsnapshot_cow/writer_v2.cpp
index d3c3d59..ee445a2 100644
--- a/fs_mgr/libsnapshot/libsnapshot_cow/writer_v2.cpp
+++ b/fs_mgr/libsnapshot/libsnapshot_cow/writer_v2.cpp
@@ -174,7 +174,7 @@
         current_data_pos_ = next_data_pos_;
     }
 
-    LOG_INFO << "Batch writes: " << batch_write_ ? "enabled" : "disabled";
+    LOG_INFO << "Batch writes: " << (batch_write_ ? "enabled" : "disabled");
 }
 
 void CowWriterV2::InitWorkers() {