[alien] fix potential leak in TAlienCollection::CheckIfOnline
[alien] fix potential leak in TAlienCollection::CheckIfOnline

Created list was not always deleted correctly
root-mirror/root,karies/root,karies/root,root-mirror/root,karies/root,karies/root,karies/root,root-mirror/root,olifre/root,karies/root,root-mirror/root,root-mirror/root,root-mirror/root,olifre/root,karies/root,karies/root,root-mirror/root,olifre/root,olifre/root,olifre/root,olifre/root,root-mirror/root,root-mirror/root,karies/root,olifre/root,karies/root,olifre/root,root-mirror/root,root-mirror/root,olifre/root,karies/root,olifre/root,olifre/root