test: fixing CI compilation of test_transaction.cc

Fixing a compilation warning in test_transaction.cc, as the CI
builds it with '-Werror'.

See https://jenkins.ceph.com/job/ceph-pull-requests/129517/

Signed-off-by: Ronen Friedman <[email protected]>

Author: ronen-fr

src/test/objectstore/test_transaction.cc

@@ -92,7 +92,6 @@ ObjectStore::Transaction generate_transaction()
 
   coll_t acid;
   object_t aobj("another_test_name");
-  snapid_t asnap(0);
   hobject_t ahoid(obj, "another_key", snap, 0, 0, "another_nspace");
   ghobject_t aoid(hoid);
   std::set<string> keys;
@@ -153,7 +152,6 @@ TEST(Transaction, GetNumBytes)
 
   coll_t acid;
   object_t aobj("another_test_name");
-  snapid_t asnap(0);
   hobject_t ahoid(obj, "another_key", snap, 0, 0, "another_nspace");
   ghobject_t aoid(hoid);
   std::set<string> keys;