typo(clock_cache) fix incomplete message typo (#9638)

Summary:
`LRU` should be `CLOCK`.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9638

Reviewed By: mrambacher

Differential Revision: D34523550

Pulled By: jay-zhuang

fbshipit-source-id: ca06ada1aac45d3707016c1590541287dab6ef79

cache/clock_cache.cc

@@ -687,7 +687,7 @@ Status ClockCacheShard::Insert(const Slice& key, uint32_t hash, void* value,
   Status s;
   if (out_handle != nullptr) {
     if (handle == nullptr) {
-      s = Status::Incomplete("Insert failed due to LRU cache being full.");
+      s = Status::Incomplete("Insert failed due to CLOCK cache being full.");
     } else {
       *out_handle = reinterpret_cast<Cache::Handle*>(handle);
     }