Invalidate the people cache on Contacts provider changes.

The Contacts database only seem to notify that a change has happened, not
which row was changed.  We simply invalidate the whole cache on changes.

Added an info log for even 100th invalidation, so we can see how often it happens.

Bug: 17466975
Change-Id: I9988ea8db776c88afd835a4b3c50b9a982a309d0
1 file changed