Fix unused parameter warnings in tests

test/beast/core/bind_handler.cpp

@@ -230,7 +230,7 @@ public:
 
         template<class F, class Alloc>
         void
-        post(F&& f, Alloc const& a)
+        post(F&&, Alloc const&)
         {
             // shouldn't be called since the enclosing
             // networking wrapper only uses dispatch
@@ -239,7 +239,7 @@ public:
 
         template<class F, class Alloc>
         void
-        defer(F&& f, Alloc const& a)
+        defer(F&&, Alloc const&)
         {
             // shouldn't be called since the enclosing
             // networking wrapper only uses dispatch