handle 0 properly when using v-bind for input value (fix #2015)
handle 0 properly when using v-bind for input value (fix #2015)

galenyuan/vue,th0r/vue,seedalpha/vue,galenyuan/vue,shupan123/vue-fixed-type,Endika/vue,seedalpha/vue,fergaldoyle/vue,Endika/vue,th0r/vue,Endika/vue,th0r/vue,fergaldoyle/vue,seedalpha/vue,diermengdierme/vue,galenyuan/vue,shupan123/vue-fixed-type,shupan123/vue-fixed-type,fergaldoyle/vue,diermengdierme/vue,diermengdierme/vue