Specify the setup path in the IBus component XML (#16)

It's always good to specify the setup path explicitly. If it's not specified,
ibus-setup finds ibus-setup-array in libexec, assuming ibus-array uses the same
libexec as ibus. Depending on this fallback makes it difficult to migrate from
FHS 2.0 (/usr/lib) to FHS 3.0 (/usr/libexec).

Author: changwoo