Remove v2_writer lseek call

Removing lseek call as writefully() should be sufficient in ensuring our
fd is moved to the correct spot

Test: cow_api_test
Change-Id: I404b192335ab1672ed61de426e17e63ab9d51ece
diff --git a/fs_mgr/libsnapshot/libsnapshot_cow/writer_v2.cpp b/fs_mgr/libsnapshot/libsnapshot_cow/writer_v2.cpp
index a6f449f..63bed07 100644
--- a/fs_mgr/libsnapshot/libsnapshot_cow/writer_v2.cpp
+++ b/fs_mgr/libsnapshot/libsnapshot_cow/writer_v2.cpp
@@ -262,11 +262,6 @@
         return false;
     }
 
-    if (lseek(fd_.get(), sizeof(CowHeader) + header_.buffer_size, SEEK_SET) < 0) {
-        PLOG(ERROR) << "lseek failed";
-        return false;
-    }
-
     InitPos();
     InitBatchWrites();