esp_http_server: Fixed a bug which could cause issues with LRU purge

LRU counter should be started from 1, and not 0, so that all checks
work fine.

Closes https://github.com/espressif/esp-idf/issues/4753

components/esp_http_server/src/httpd_sess.c

@@ -202,7 +202,7 @@ static int fd_is_valid(int fd)
 static inline uint64_t httpd_sess_get_lru_counter(void)
 {
     static uint64_t lru_counter = 0;
-    return lru_counter++;
+    return ++lru_counter;
 }
 
 void httpd_sess_delete_invalid(struct httpd_data *hd)