Fix a memory leak in c_test (#8237)

Summary:
Don't call ```rocksdb_cache_disown_data()``` as it causes the memory allocated for ```shards_``` to be leaked.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8237

Reviewed By: jay-zhuang

Differential Revision: D28039061

Pulled By: anand1976

fbshipit-source-id: c3464efe2c006b93b4be87030116a12a124598c4

db/c_test.c

@@ -2928,7 +2928,6 @@ int main(int argc, char** argv) {
   rocksdb_readoptions_destroy(roptions);
   rocksdb_writeoptions_destroy(woptions);
   rocksdb_compactoptions_destroy(coptions);
-  rocksdb_cache_disown_data(cache);
   rocksdb_cache_destroy(cache);
   rocksdb_comparator_destroy(cmp);
   rocksdb_dbpath_destroy(dbpath);