fix split-window path for tmux 1.9
fix split-window path for tmux 1.9

abhisood/dotfiles,pekosi/dotfiles,joeandrews/dotfiles,jacobxk/dotfiles-1,jacobxk/dotfiles-1,jbargu/dotfiles,ptgamr/dotfiles,SlyDen/dotfiles,zhenglaizhang/dotfiles-1,OctavianRotari/dotfiles,dyong0/dotfiles,paulhirschi/dotfiles,OctavianRotari/dotfiles,neutrinog/dotfiles,fieteboerner/dotfiles,patnolanireland/dotfiles,patnolanireland/dotfiles,fieteboerner/dotfiles,Jooho/dotfiles_mac,bbtb1982/dotfiles,Boukefalos/dotfiles,bbtb1982/dotfiles,damca/dotfiles-ubuntu,pekosi/dotfiles,zhenglaizhang/dotfiles-1,damca/dotfiles-ubuntu,nicknisi/dotfiles,NerdPad/dotfiles,ptgamr/dotfiles,nicknisi/dotfiles,gblock0/dotfiles_unstable,fieteboerner/dotfiles,jbargu/dotfiles,Reesi82/dotfiles,nicknisi/dotfiles,Jooho/dotfiles_mac