Bug in fq_t and lb_t (when used via ZMQ_EVENTS option) fixed

src/fq.cpp

@@ -148,8 +148,11 @@ bool zmq::fq_t::has_in ()
     for (int count = active; count != 0; count--) {
         if (pipes [current]->check_read ())
             return true;
-        current++;
-        if (current >= active)
+
+        //  Deactivate the pipe.
+        active--;
+        pipes.swap (current, active);
+        if (current == active)
             current = 0;
     }
 

src/lb.cpp

@@ -135,10 +135,10 @@ bool zmq::lb_t::has_out ()
         if (pipes [current]->check_write ())
             return true;
 
+        //  Deactivate the pipe.
         active--;
-        if (current < active)
-            pipes.swap (current, active);
-        else
+        pipes.swap (current, active);
+        if (current == active)
             current = 0;
     }