revert(3p/git): Revert merge of git upstream at v2.26.2

This causes cgit to serve error pages, which is undesirable.

This reverts commit 5229c9b232, reversing
changes made to f2b211131f.

third_party/git/trace.c

@@ -88,6 +88,8 @@ static int prepare_trace_line(const char *file, int line,
 	if (!trace_want(key))
 		return 0;
 
+	set_try_to_free_routine(NULL);	/* is never reset */
+
 	/* unit tests may want to disable additional trace output */
 	if (trace_want(&trace_bare))
 		return 1;