transaction: abort does not need to use recursive deletion

Recursion is unnecessary, because we're deleting all transaction jobs
anyway. And the recursive deletion produces debug messages that are
pointless in transaction abort.

src/core/transaction.c

@@ -51,7 +51,7 @@ void transaction_abort(Transaction *tr) {
         assert(tr);
 
         while ((j = hashmap_first(tr->jobs)))
-                transaction_delete_job(tr, j, true);
+                transaction_delete_job(tr, j, false);
 
         assert(hashmap_isempty(tr->jobs));
 }