internal: clean up unrelated comment

The comment about routes is likely has been introduced because
cartridge.roles.crud-router role was based on cartridge.roles.metrics
role, see [1].

1. https://github.com/tarantool/metrics/blob/5ac763d87b8ba140147a66a7ca60b35daf44b826/cartridge/roles/metrics.lua#L170

Part of #332

Author: DifferentialOrange

cartridge/roles/crud-router.lua

@@ -1,7 +1,6 @@
 local crud = require('crud')
 local stash = require('crud.common.stash')
 
--- removes routes that changed in config and adds new routes
 local function init()
     crud.init_router()
     stash.setup_cartridge_reload()