revert sync prop (fix #1262)
revert sync prop (fix #1262)

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