imlib.c: fill_text_bg: Simplify background initialization (patch by penma)
imlib.c: fill_text_bg: Simplify background initialization (patch by penma)

fixes valgrind warning about use of uninitialized values

yusiwen/feh,Caellian/feh,BlackLight/feh,yusiwen/feh,Caellian/feh,Caellian/feh,yusiwen/feh,BlackLight/feh,BlackLight/feh,Caellian/feh