winhttp: Don't report data pending in the socket.

Some installers make assumptions about the size of the internal buffer. We could
exceed that size when there's enough data pending in the socket.

dlls/winhttp/net.c

@@ -740,16 +740,8 @@ ULONG netconn_query_data_available( netconn_t *conn )
     if(!netconn_connected(conn))
         return 0;
 
-    if(conn->secure) {
+    if(conn->secure)
         return conn->peek_len;
-    }else {
-#ifdef FIONREAD
-        ULONG unread;
-
-        if(!ioctlsocket(conn->socket, FIONREAD, &unread))
-            return unread;
-#endif
-    }
 
     return 0;
 }