abrtd: fix on top of "prevent possible leak of malloced worst_dir"

In previous change I deleted freeing of worst_dir in the block,
frreing it after it instead, but the block wasn't an if() -
it was a loop! This change reinstates freeing inside the loop.

Thanks Jakub for spotting it!

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>