auc: update to version 0.2.4

auc: update to version 0.2.4

A stray ')' made auc skip the check if all mandatory fields of a
branch are present. Fix paranthesis in that if-clause to actually
check for all fields.

Don't even fetch package lists if checking only for release.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>