Update content description after updating primary

Here's what went wrong: we set content description of photos in
CompactRawContactsEditorView.getPhotos() (see ag/834274) and then
we modify "primary" before entering photo picker (see ag/854600).

We need to update content description of photos after modifying
"primary" to reflect the change in which photo is checked.

Bug 27881948

Change-Id: Iad9723c9adbeaf8396fc46c578cc4a519d9ba85a
(cherry picked from commit 5a59c26c4e43fedcd449dfae97ea435f1ce885e3)