[phone] Enable flight mode, the cellular data indicator still be ON in settings.

[Hannah Zhu]

Information:
phablet@ubuntu-phablet:~$ system-image-cli -i
current build number: 22
device name: turbo
channel: ubuntu-touch/rc/meizu-pd.en
last update: 2016-11-21 16:17:17
version version: 22
version ubuntu: 20161118
version device: 20160824-d33b825
version custom: 20160831-992-8-12

Precondition:
SIM cards inserted.

Step:
1.Go to system settings, and enable flight mode
2.Go to Cellular settings Panel, and check the cellular data indicator.

Actual result:
Enable flight mode, the cellular data indicator still be ON.

Expect result:
The cellular data indicator should be OFF.

Related test case:
https://prod.practitest.com/p/1548/qtest_runs/6921297/edit