network: check access point if is exists before connecting

Do not connect to the access point if not exists
when trun on wireless switch.

tower: https://tower.im/projects/8f19f0bf0e754f0b82ef2c24bc230973/todos/3a3ed3e814e2463691cfe30678b8db3e/
Change-Id: I17eb3b42ebb9c7601298b8a18af21b06629d66e2