build: edify: use set_metadata for backuptool

Also use saner permissions on backuptool.sh

Change-Id: I50742b51867aa358f5924b8dc208833092a35bd9
Merge remote-tracking branch 'cm/cm-11.0' into cm-11.0
Merge branch 'cm-11.0' of https://github.com/Cl3Kener/android_build into cm-11.0

'Merge.