[Libreoffice] Review request: fix for crash fdo#36495

[Tor Lillqvist]

http://cgit.freedesktop.org/libreoffice/libs-core/commit/?id=37b8567fc76b78b1844461926175ba6919b8c7bd

A proper fix would be to  make sure the code doesn't even get into a situation where it feels the need to try to use elements in an empty vector, but whatever...

Not marked as a mostly annoying bug, but it is a crasher, so perhaps should be cherry-picked to the -3-4 or even -3-4-0 branches?

--tml