Fixing missed call badge query

+ Previously the query for the missed calls only checked if the
calllog is_read column was equal to 1. The situation where a callog
entry exists because it was copied from another user's calllog (such
as for File based encryption), the value of is_read is null rather
than 0 or 1.
+ This CL updates the query to return those calllog entries that have
null for is_read too. This logic matches the logic for making a
calllog entry bold when it's unread.

Bug: 27168340
Change-Id: I73dba6920a3eaf352feae4d23cc3f55d51bd1efd