proxy client: fix building Listener map

src/dht_proxy_client.cpp

@@ -40,9 +40,8 @@ struct DhtProxyClient::OperationState {
 
 struct DhtProxyClient::Listener
 {
-    explicit Listener(OpValueCache&& c):
-        cache(std::move(c))
-    {}
+    Listener(OpValueCache&& c):
+        cache(std::move(c)) {}
 
     OpValueCache cache;
     CacheValueCallback cb;

src/op_cache.h

@@ -33,7 +33,7 @@ struct OpCacheValueStorage
 
 class OpValueCache {
 public:
-    explicit OpValueCache(ValueCallback&& cb) noexcept : callback(std::forward<ValueCallback>(cb)) {}
+    OpValueCache(ValueCallback&& cb) noexcept : callback(std::forward<ValueCallback>(cb)) {}
     explicit OpValueCache(OpValueCache&& o) noexcept : values(std::move(o.values)), callback(std::move(o.callback)) {
         o.callback = {};
     }