fix symfony version for Travis Ci environment
fix symfony version for Travis Ci environment

webkod3r/AliDatatableBundle,AliHichem/AliDatatableBundle,waldo2188/DatatableBundle,kuldipem/AliDatatableBundle,zgoniaiko/AliDatatableBundle,kuldipem/AliDatatableBundle,zgoniaiko/AliDatatableBundle,webkod3r/AliDatatableBundle,vouchedfor/AliDatatableBundle,waldo2188/DatatableBundle,vouchedfor/AliDatatableBundle,AliHichem/AliDatatableBundle