Fix filesystem enrollment
Fix filesystem enrollment

We would always enrol a single key, deleting any existing keys in the
database. Fix that up.

android-ia/platform_external_uefi_shim,rhinstaller/shim,rhinstaller/shim,CyanogenMod/android_external_uefi_shim,CyanogenMod/android_external_uefi_shim,CyanogenMod/android_external_uefi_shim,rhinstaller/shim,android-ia/platform_external_uefi_shim,android-ia/platform_external_uefi_shim