Prompts to "Add account" should add a google one (2/2)

* Also replace use of deprecated
  FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET with
  FLAG_ACTIVITY_NEW_DOCUMENT
* Switch ACTION_SYNC_SETTINGS for contacts
  providers so the Settings activity says
  "Accounts" instead of "Add Account"

Bug 29185471
Bug 30080351

Change-Id: Ibb5fee73021a4f2a11c3dd2241fcd92e2c93220d