Log both the source of the source_date_epoch and the resulting
source_date_epoch in all cases.
Also, now that we are determining the source_date_epoch successfully for both
yocto and non-yocto kernels, remove the inherits_class('kernel') exception.
We will log a failure to find a source_date_epoch for kernels as well.
Signed-off-by: Douglas Royds <douglas.royds@taitradio.com> Signed-off-by: Ross Burton <ross.burton@intel.com>
