InCallUI: Replace deprecated string resources.

alert_yes/no were deprecated in 4.4, and discontinued in 4.4.3.
Replace them with the system's "yes/no"

Change-Id: Ia0b2a68ffb7098c3c4ba70856e831a61161e2886
Merge pull request #5 from omnirom/android-4.4

InCallUI: Replace deprecated string resources.