Merge fix for zeromq/zeromq4-1#52, getsockopt ZMQ_RCVMORE now resets all bits

src/socket_base.cpp

@@ -361,6 +361,7 @@ int zmq::socket_base_t::getsockopt (int option_, void *optval_,
             EXIT_MUTEX();
             return -1;
         }
+        memset(optval_, 0, *optvallen_);
         *((int*) optval_) = rcvmore ? 1 : 0;
         *optvallen_ = sizeof (int);
         EXIT_MUTEX();