Disable up button for Voicemail > Setup.
Disable up button for Voicemail > Setup.

Check the keys instead of the reference.

This happens because...

1) Closing the ringtone dialog causes the activity's onResume to
trigger.

2) This removes all the preferences, adds call_feature_settings
again and updates all the references in the call settings activity.
We do this to appropriately remove/add preferences, depending on
changes to configuration.

3) But, the OLD voicemail screen preference screen is showing. Any
clicks to it are still handled by the activity, but the reference
to the preferences clicked is no longer the same as the class
variables stored by activity.

4) Thus, comparison for equality is not evaluating to true.

Checking the keys instead ensures that the code to handle the
settings being clicked is executed. Conceptually this is still
correct, just more precise than checking references.  We can
revert back to references once we migrate the voicemail settings
to its own activity.

Bug: 18321866
Bug: 17019623
Change-Id: Ide2cb79ea7e9c5d41937f93eb9d3cd6c0a3ebfed

md5555/android_packages_services_Telephony