fix regression in entry constructor (#950)

include/libtorrent/entry.hpp

@@ -135,7 +135,7 @@ namespace libtorrent
 
 		// construct an empty entry of the specified type.
 		// see data_type enum.
-		explicit entry(data_type t);
+		entry(data_type t);
 
 		// hidden
 		entry(entry const& e);

test/test_bencoding.cpp

@@ -134,6 +134,13 @@ TORRENT_TEST(undefined_node2)
 	TEST_EQUAL(encode(e), "d4:info0:e");
 }
 
+TORRENT_TEST(implicit_construct)
+{
+	entry e(entry::list_t);
+	e.list().push_back(entry::list_t);
+	TEST_EQUAL(e.list().back().type(), entry::list_t);
+}
+
 #ifndef TORRENT_NO_DEPRECATE
 TORRENT_TEST(lazy_entry)
 {