camera: Re-add micromanagement of preview metadata

 * Some devices still have issues without this fix.

Change-Id: Iae2d4410086fb38bf7f9abeee62c05cae824d436
Merge remote-tracking branch 'cyanogen/cm-10.2' into cm-10.2
Merge branch 'cm-10.2' of https://github.com/Quarx2k/android_frameworks_av into CB4.3