classes/buildhistory: handle additional files at recipe level
Avoid an error when attempting to remove previous data if it's not a
subdirectory - we were assuming that anything that wasn't named "latest"
or "latest_srcrev" had to be a directory. This makes it possible to have
a buildhistory_emit_pkghistory_append which writes additional files at
the recipe level.
Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com> Signed-off-by: Ross Burton <ross.burton@intel.com>
