Merge branch 'bugfix/log_free_level_entry' into 'master'

log: fix minor memory leak when cleaning list of log levels

Closes IDF-710

See merge request idf/esp-idf!5260

components/log/log.c

@@ -174,8 +174,10 @@ void esp_log_level_set(const char* tag, esp_log_level_t level)
 
 void clear_log_level_list()
 {
-    while( !SLIST_EMPTY(&s_log_tags)) {
+    uncached_tag_entry_t *it;
+    while((it = SLIST_FIRST(&s_log_tags)) != NULL) {
         SLIST_REMOVE_HEAD(&s_log_tags, entries );
+        free(it);
     }
     s_log_cache_entry_count = 0;
     s_log_cache_max_generation = 0;