[fix] undefined vars in install script
[fix] undefined vars in install script

wallabag/wallabag,modos189/wallabag,egilli/wallabag,wallabag/wallabag,X-dark/wallabag,X-dark/wallabag,antoniosejas/wallabag,egilli/wallabag,pmichelazzo/wallabag,aarizkuren/wallabag,pmichelazzo/wallabag,ekospinach/wallabag,modos189/wallabag,aarizkuren/wallabag,kwangkim/wallabag,shtrom/wallabag,egilli/wallabag,mubassirhayat/wallabag,FabienM/wallabag,kwangkim/wallabag,wangjun/wallabag,aarizkuren/wallabag,kevmeyer/wallabag,kevmeyer/wallabag,egilli/wallabag,pmichelazzo/wallabag,pmichelazzo/wallabag,FabienM/wallabag,harikt/wallabag,ekospinach/wallabag,milanaleksic/wallabag,shtrom/wallabag,antoniosejas/wallabag,shtrom/wallabag,harikt/wallabag,wangjun/wallabag,X-dark/wallabag,pmichelazzo/wallabag,shtrom/wallabag,modos189/wallabag,kevmeyer/wallabag,FabienM/wallabag,egilli/wallabag,X-dark/wallabag,wallabag/wallabag,X-dark/wallabag,freddyb/wallabag,aarizkuren/wallabag,ekospinach/wallabag,wangjun/wallabag,antoniosejas/wallabag,kwangkim/wallabag,mubassirhayat/wallabag,kevmeyer/wallabag,FabienM/wallabag,milanaleksic/wallabag,mubassirhayat/wallabag,milanaleksic/wallabag,shtrom/wallabag,freddyb/wallabag,harikt/wallabag,freddyb/wallabag