Fix NullPointerException on locale change.

Change-Id: Ib6f33c324164b4fda59a3cd3d7f00da82396e04d
Fix crash of date selector.

How to reproduce:
- Open date filter
- Turn off screen
- Turn on screen
- Reopen date filter

Also move around code a bit to follow existing design patterns more
closely.

Change-Id: Ibd46a09db6c5fb4623a1ef8062af971aee0e1a60

Conflicts:

	src/com/android/contacts/callstats/CallStatsActivity.java
	src/com/android/contacts/callstats/DoubleDatePickerDialog.java