Camera: Fix for the AF brackets issues in Face Detetcion.

Also disable the FD start flag from stopPreview.

CRs-Fixed:  453944
	modified:   src/com/android/camera/PhotoModule.java

Change-Id: I7ab17154f461d90db2744dbae7aeff518ccd7cc8
(cherry picked from commit e1b82c95910d783cb531c81b5f23552bf26e6cc6)