ibus 1.5.29 has characters appear out of order during conversion

[Chua Hou]

Appears to be an issue in some conditions, such as when using xim mode like we do. See 2616 in ibus/ibus for what appears to be a similar issue, closed as wontfix. Hopefully it'll work in 1.5.30.

Workaround was added in 995343b, by using 1.5.28.