Revert "Follow up fix for the log level "everything""

This reverts commit a6428d2376034d619f342897d3ce415b3f9a3584.
diff --git a/src/logging.c b/src/logging.c
index 995fcd7..214ad2a 100644
--- a/src/logging.c
+++ b/src/logging.c
@@ -135,9 +135,6 @@
 /*! \brief convert a numeric log level into human-readable string */
 const char *log_level_str(unsigned int lvl)
 {
-	/* backwards compatibility */
-	if (lvl == 0)
-		return loglevel_strs[0].str;
 	return get_value_string(loglevel_strs, lvl);
 }