Calendar: Display a toast when no maps app is installed

When no maps app is installed, slide down the status bar and press
the map button of the calendar event. What results is a dialog
stating "Unfortunately, Calendar has stopped."

Handle this by trying activityNotFoundException and adding a toast.

CRs-fixed: 955658
Change-Id: I0d394bb6af963d16e3096d44816ca6af2d7aeccd
(cherry picked from commit 8117611)