Move smart dialer initialization to onStart().

The SmartDialCursorLoader expects the SmartDialPrefix map to be
initialized when it's created. As
- the loader is initialized in SmartDialSearchFragment's onStart and
- the fragment's onStart is called asynchronously after the activity's
  onStart and
- the map initialization happens in
  SmartDialPrefix.initializeNanpSettings() and
- the above method is currently called in the activity's onResume()

we have a race condition between the activity's onResume() and the
fragment's onStart() (at least when processing a dial intent, which is
what causes the dialpad fragment to be immediately shown).

Fix that race condition by moving the initialization into the activity's
onStart() and running it before calling the super method to ensure it
happens before fragments are started.

JIRA:NIGHTLIES-760
Change-Id: I9767cbba3b177fdd5b1de86914cb1e40d20835ab