Log Message:
Update ibus to 1.5.4.

News of 1.5.0
* Improve ibus performance by replace some python components with vala \ 
implementations.
* Improve IME switch UI and logic, and support shortcut customization.
Integrate IME and XKB keyboard layouts. Now ibus can manage both IME and XKB layouts.
* Improve gobject-introspection support.
* Improve vala language support.
* New functions to restrict config signal: ibus_config_watch/unwatch
* Remove gnome-icon-theme-legacy dependency.
* Add version property in IBusEngineDesc.
* Add IBusProperty.symbol for the short label.
* Support dconf 0.13.4
* Add ibus command line tool.
* Improve unit test.
* ibus-daemon now monitors .xml files by default
* "make check" does not require "make install"
* Support out-of-tree build
* pygobject override is added to help migrate from the old python binding
* Many bug fixings.