bugfix: Add shmtx unlock

[u5surf]

ngx_http_vhost_traffic_status_shm_add_node does not unlock if it returns from line 133 nevertheless it acquires the lock at line 107.

nginx-module-vts/src/ngx_http_vhost_traffic_status_shm.c

Lines 107 to 133 in 0009b3b

	ngx_shmtx_lock(&shpool->mutex);
	/* find node */
	hash = ngx_crc32_short(key->data, key->len);
	node = ngx_http_vhost_traffic_status_find_node(r, key, type, hash);
	/* set common */
	if (node == NULL) {
	init = NGX_HTTP_VHOST_TRAFFIC_STATUS_NODE_NONE;
	/* delete lru node */
	lrun = ngx_http_vhost_traffic_status_find_lru(r);
	if (lrun != NULL) {
	ngx_rbtree_delete(ctx->rbtree, lrun);
	ngx_slab_free_locked(shpool, lrun);
	}
	size = offsetof(ngx_rbtree_node_t, color)
	+ offsetof(ngx_http_vhost_traffic_status_node_t, data)
	+ key->len;
	node = ngx_slab_alloc_locked(shpool, size);
	if (node == NULL) {
	shm_info = ngx_pcalloc(r->pool, sizeof(ngx_http_vhost_traffic_status_shm_info_t));
	if (shm_info == NULL) {
	return NGX_ERROR;