re #308.
re #308.

Added check in case the ids are the same (you should not be able to link a sentence to itself).

git-svn-id: 776ea4b3e47339c5b8782ec5e9346c740e073fb4@1799 e0e46c49-be69-4f5a-ad62-21024a331aea

hans/tatoeba2,hans/tatoeba2,hans/tatoeba2