Fix bug #2619140 (ANR: calendar provider does too much in onCreate())

- make the CalendarProvider2 onCreate() similar to the ContactsProvider2
- do lazy initialization and use the previous Timezone checker thread to run the verifyAccounts()
- get the writable database reference as soon as possible

Change-Id: I9e840ae47d7aacfe48c5e4ebc22b509189bb51bd
Merge commit 'ae4e50b2c35fe4549d1df6568544aa72057dcbe1' into oxygen_1006

* commit 'ae4e50b2c35fe4549d1df6568544aa72057dcbe1':
  Fix bug #2619140 (ANR: calendar provider does too much in onCreate())

Conflicts:
	src/com/android/providers/calendar/CalendarProvider2.java