libplugin: fix LOG_TRACE for plugins

A log event LOG_TRACE submitted by a plugin was being logged as
**BROKEN** by lightningd before this commit.

Changelog-Fixed: plugins can now log events under the LOG_TRACE flag.

Signed-off-by: Lagrang3 <[email protected]>

Author: Lagrang3

lightningd/plugin.c

@@ -498,7 +498,7 @@ static const char *plugin_log_handle(struct plugin *plugin,
 		 || level == LOG_IO_OUT) {
 		return tal_fmt(plugin,
 			       "Unknown log-level %.*s, valid values are "
-			       "\"debug\", \"info\", \"warn\", or \"error\".",
+			       "\"trace\", \"debug\", \"info\", \"warn\", or \"error\".",
 			       json_tok_full_len(leveltok),
 			       json_tok_full(plugin->buffer, leveltok));
 	}

plugins/libplugin.c

@@ -1835,7 +1835,8 @@ void plugin_logv(struct plugin *p, enum log_level l,
 
 	json_object_start(js, "params");
 	json_add_string(js, "level",
-			l == LOG_DBG ? "debug"
+			l == LOG_TRACE ? "trace"
+			: l == LOG_DBG ? "debug"
 			: l == LOG_INFORM ? "info"
 			: l == LOG_UNUSUAL ? "warn"
 			: l == LOG_TRACE ? "trace"