remove unused variables (#4013)

Signed-off-by: Rama <rama.rao@salesforce.com>

source/common/stats/thread_local_store.cc

@@ -67,14 +67,12 @@ std::vector<GaugeSharedPtr> ThreadLocalStoreImpl::gauges() const {
 }
 
 std::vector<ParentHistogramSharedPtr> ThreadLocalStoreImpl::histograms() const {
-  // Handle de-dup due to overlapping scopes.
   std::vector<ParentHistogramSharedPtr> ret;
-  std::unordered_set<std::string> names;
   Thread::LockGuard lock(lock_);
   // TODO(ramaraochavali): As histograms don't share storage, there is a chance of duplicate names
   // here. We need to create global storage for histograms similar to how we have a central storage
   // in shared memory for counters/gauges. In the interim, no de-dup is done here. This may result
-  // in histograms with duplicate names, but until shared storage is implementing it's ultimately
+  // in histograms with duplicate names, but until shared storage is implemented it's ultimately
   // less confusing for users who have such configs.
   for (ScopeImpl* scope : scopes_) {
     for (const auto& name_histogram_pair : scope->central_cache_.histograms_) {