Updated missed call notification behaviour

Change-Id: Id32110413fbb5fa4ae4c3478e70f54d211b78389

Missed call notification

1. If the phone account has multi user capability, the notification
   is shown in current user.

2. If the phone account has no multi user capability, the notification
   is shown in the user that owns the phone account of the call

3. Whenever user is switched, reload missed call from database and post
   notifications if necessary.

Change-Id: Id32110413fbb5fa4ae4c3478e70f54d211b78389