hooks: make hook logic memory-leak free

This helps t0401 pass while under SANITIZE=leak.

Signed-off-by: Derrick Stolee <stolee@gmail.com>

Author: derrickstolee

git.c

@@ -494,6 +494,7 @@ static int run_post_command_hook(struct repository *r)
 
 	run_post_hook = 0;
 	strvec_clear(&sargv);
+	strvec_clear(&opt.args);
 	setenv("COMMAND_HOOK_LOCK", "false", 1);
 	return ret;
 }

hook.c

@@ -347,12 +347,15 @@ int run_hooks_l(struct repository *r, const char *hook_name, ...)
 {
 	struct run_hooks_opt opt = RUN_HOOKS_OPT_INIT;
 	va_list ap;
+	int result;
 	const char *arg;
 
 	va_start(ap, hook_name);
 	while ((arg = va_arg(ap, const char *)))
 		strvec_push(&opt.args, arg);
 	va_end(ap);
 
-	return run_hooks_opt(r, hook_name, &opt);
+	result = run_hooks_opt(r, hook_name, &opt);
+	strvec_clear(&opt.args);
+	return result;
 }