Problem: socket_poller_t initialization reorder

Solution: initialize class variable in the same order as they are
defined.

src/socket_poller.cpp

@@ -34,14 +34,14 @@
 zmq::socket_poller_t::socket_poller_t () :
     tag (0xCAFEBABE),
     need_rebuild (true),
-    poll_size(0),
-#if defined ZMQ_POLL_BASED_ON_SELECT
-    maxfd(0),
-#endif
-    use_signaler (false)
+    use_signaler (false),
+    poll_size(0)
 #if defined ZMQ_POLL_BASED_ON_POLL
     ,
     pollfds (NULL)
+#elif defined ZMQ_POLL_BASED_ON_SELECT
+    ,
+    maxfd(0)
 #endif
 {
 #if defined ZMQ_POLL_BASED_ON_SELECT