server/sws: fix asan warning on use of uninitialized variable

tests/server/sws.c

@@ -2206,6 +2206,7 @@ int main(int argc, char *argv[])
     fd_set output;
     struct timeval timeout = {0, 250000L}; /* 250 ms */
     curl_socket_t maxfd = (curl_socket_t)-1;
+    int active;
 
     /* Clear out closed sockets */
     for(socket_idx = num_sockets - 1; socket_idx >= 1; --socket_idx) {
@@ -2253,6 +2254,7 @@ int main(int argc, char *argv[])
       /* Timed out - try again */
       continue;
     }
+    active = rc; /* a positive number */
 
     /* Check if the listening socket is ready to accept */
     if(FD_ISSET(all_sockets[0], &input)) {
@@ -2264,11 +2266,13 @@ int main(int argc, char *argv[])
         if(CURL_SOCKET_BAD == msgsock)
           goto sws_cleanup;
       } while(msgsock > 0);
+      active--;
     }
 
     /* Service all connections that are ready */
-    for(socket_idx = 1; socket_idx < num_sockets; ++socket_idx) {
+    for(socket_idx = 1; (socket_idx < num_sockets) && active; ++socket_idx) {
       if(FD_ISSET(all_sockets[socket_idx], &input)) {
+        active--;
         if(got_exit_signal)
           goto sws_cleanup;