Fix crash

It seems that not all machines (at least Jenkins Windows build agent)
have HKCU\Keyboard Layout\Substitutes in which case hkl suddenly is null.
This change ensures that hkl always has a value.
Merge remote-tracking branch 'origin/FlexBridgeBeta' into fw/KeyboardingV2

Change-Id: Ie79f68610bd648895f5ebb2d54d0cfcdb1f2364c