ContactsCommon : Address loader reset bug

If the loader is reset, the adapter partitions need to be cleared,
without it the app tries to access a closed cursor.

Reproduction steps :

Add to contacts
Type a two letters
Enjoy force-close

Change-Id: I76474724bd46512929306ba04a4d156a9b39d9f3
(cherry picked from commit 17c76fe3179f846c2c701e887350b508f6726ff6)
The FastScroller is not working properly.

If you have a large number of contacts in the last section of contacts list,
when you scroll the list, the fast scroll bar will work improperly, it will scroll back.

The reason is that when we scroll to the last section, the next position of the next section is -1 but not the count of the contacts.

Change-Id: I058b3e6c88e8aaeabbfed291296e02dfd775018e