Reduce logging of flattened Preferences

Bug: 11901390

Change-Id: I9f2e27e769fd745be01bb2c12a7f07b45aa0b905
Merge tag 'android-4.4.2_r1' of https://android.googlesource.com/platform/packages/apps/Camera2 into kk4.4

Android 4.4.2 Release 1