Simple change to default from 15 to 7 making handful of devices that have 4 softkeys require a overlay. Kill the need for sgs common overlay in vendor/slim

Change-Id: I480d4939cda4c4955184500c4daeddced207ded8
Merge "Simple change to default from 15 to 7 making handful of devices that have 4 softkeys require a overlay. Kill the need for sgs common overlay in vendor/slim" into jb4.2