Fix popup dialog show wrong device name

- Current EditText value will set to preference text if we click
OK in EditTextPreferenceDialogFragment. We will set preference
text to default when click cancel in DeviceNameWarningDialog.

Change-Id: Iab9561953b58276e98ee68d9196fa18e0dc3d78c
Fixes: 115693838
Test: make RunSettingsRoboTests
5 files changed