Fix bug #15001610 Java crash in settings is observed while adding Google account on wiped device

- make WifiPickerActivity a SettingsActivity (as it was long overdue)
- move code from the overide of PreferenceActivity.startWithFragment() to
SettingsActivity.startPreferencePanel(...)

Change-Id: Ibc42056fdc84e01004e15c3779073e5451fd02a1
2 files changed