chord_composer: fix lotem/squirrel Issue #22, extra leading bom character in preedit.
chord_composer: fix lotem/squirrel Issue #22, extra leading bom character in preedit.

Prcuvu/librime,Prcuvu/librime,kionz/librime,j717273419/librime,rime/librime,jakwings/librime,j717273419/librime,rime/librime,rime/librime,j717273419/librime,bygloam/librime,rwduzhao/librime,kionz/librime,rwduzhao/librime,bygloam/librime,rwduzhao/librime,Prcuvu/librime,jakwings/librime,Prcuvu/librime,kionz/librime,bygloam/librime,kionz/librime,jakwings/librime,rime/librime,Prcuvu/librime