folly: fix -Wunused-parameter in opt mode

Summary: Fix a few remaining unused parameters, that are exposed only in opt build.

Reviewed By: markisaa

Differential Revision: D2878865

fb-gh-sync-id: d0d9761362220973cda14d99ab7342fbe8b1a469

folly/MPMCPipeline.h

@@ -161,12 +161,15 @@ template <class In, class... Stages> class MPMCPipeline {
 #endif
         remainingUses_(amplification),
         value_(value * amplification) {
+      (void)owner; // -Wunused-parameter
     }
 
     uint64_t use(MPMCPipeline* owner) {
       CHECK_GT(remainingUses_--, 0);
 #ifndef NDEBUG
       CHECK(owner == owner_);
+#else
+      (void)owner; // -Wunused-parameter
 #endif
       return value_++;
     }

folly/test/FBStringTest.cpp

@@ -591,7 +591,7 @@ template <class String> void clause11_21_4_7_1(String & test) {
   // exercise get_allocator()
   String s;
   randomString(&s, maxString);
-  assert(test.get_allocator() == s.get_allocator());
+  DCHECK(test.get_allocator() == s.get_allocator());
 }
 
 template <class String> void clause11_21_4_7_2_a(String & test) {