Fix bug #8139 and a thinko in [737e9b2c/lyxgit].

Fix bug #8139 and a thinko in [737e9b2c/lyxgit].

I had already noticed the above mentioned thinko and this commit
should have been part of [3285ce1d5/lygit] but somehow I managed
to lose it in the git branches game: do a branch for that, than
try a different thing in another branch, then rebase to avoid
merge conficts, and finally delete all unneeded branches. Well it
is too much easy to do the wrong thing and pick the wrong branch,
deleting the right one. I will never follow the git way anymore
and will do I was used to do with svn.