Contacts: Update dialog with the correct selected count

Delete contacts
SIM import contacts

Repro:
- Open "Delete" from the overflow menu
- Select one contact and select done in action bar
- Observe: dialog shows 1 contact to delete
- Cancel dialog and select another contact for deletion
- Select done in action bar
- Observe: dialog still shows 1 contact to delete

Change-Id: Icd9ee29f102386a5b3642614e1f7c209318c7702