confile: add dummy clearer for lxc.pivotdir

src/lxc/confile.c

@@ -141,6 +141,7 @@ static int clr_config_rootfs(const char *, struct lxc_conf *);
 
 static int set_config_pivotdir(const char *, const char *, struct lxc_conf *);
 static int get_config_pivotdir(const char *, char *, int, struct lxc_conf *);
+static int clr_config_pivotdir(const char *, struct lxc_conf *);
 
 static int set_config_utsname(const char *, const char *, struct lxc_conf *);
 static int get_config_utsname(const char *, char *, int, struct lxc_conf *);
@@ -251,7 +252,7 @@ static struct lxc_config_t config[] = {
 	{ "lxc.rootfs.options",       set_config_rootfs_options,       get_config_rootfs_options,    clr_config_rootfs_options,    },
 	{ "lxc.rootfs.backend",       set_config_rootfs_backend,       get_config_rootfs_backend,    clr_config_rootfs_backend,    },
 	{ "lxc.rootfs",               set_config_rootfs,               get_config_rootfs,            clr_config_rootfs,            },
-	{ "lxc.pivotdir",             set_config_pivotdir,             get_config_pivotdir,          NULL },
+	{ "lxc.pivotdir",             set_config_pivotdir,             get_config_pivotdir,          clr_config_pivotdir,          },
 	{ "lxc.utsname",              set_config_utsname,              get_config_utsname,           NULL },
 	{ "lxc.hook.pre-start",       set_config_hooks,                get_config_hooks,             NULL },
 	{ "lxc.hook.pre-mount",       set_config_hooks,                get_config_hooks,             NULL },
@@ -4154,3 +4155,7 @@ static inline int clr_config_rootfs_backend(const char *key, struct lxc_conf *c)
 	return 0;
 }
 
+static inline int clr_config_pivotdir(const char *key, struct lxc_conf *c)
+{
+	return 0;
+}