Name zip with journalist_filename() instead of journalist_designation
Name zip with journalist_filename() instead of journalist_designation

Instead of naming the generated zip file with the journalist_designation
which can contain spaces, it's probably better to use the output of
journalist_filename() which removes spaces explicitly, and aims to be
filesystem safe.

conorsch/securedrop,chadmiller/securedrop,harlo/securedrop,jeann2013/securedrop,ehartsuyker/securedrop,micahflee/securedrop,kelcecil/securedrop,GabeIsman/securedrop,jaseg/securedrop,kelcecil/securedrop,ehartsuyker/securedrop,heartsucker/securedrop,jeann2013/securedrop,micahflee/securedrop,micahflee/securedrop,jrosco/securedrop,jeann2013/securedrop,ageis/securedrop,pwplus/securedrop,heartsucker/securedrop,jaseg/securedrop,garrettr/securedrop,jaseg/securedrop,pwplus/securedrop,GabeIsman/securedrop,GabeIsman/securedrop,pwplus/securedrop,conorsch/securedrop,jeann2013/securedrop,garrettr/securedrop,pwplus/securedrop,conorsch/securedrop,conorsch/securedrop,harlo/securedrop,jrosco/securedrop,chadmiller/securedrop,chadmiller/securedrop,conorsch/securedrop,pwplus/securedrop,jrosco/securedrop,jaseg/securedrop,kelcecil/securedrop,harlo/securedrop,harlo/securedrop,jrosco/securedrop,ehartsuyker/securedrop,ehartsuyker/securedrop,chadmiller/securedrop,kelcecil/securedrop,ehartsuyker/securedrop,ehartsuyker/securedrop,jrosco/securedrop,harlo/securedrop,micahflee/securedrop,jeann2013/securedrop,chadmiller/securedrop,jaseg/securedrop,ageis/securedrop,garrettr/securedrop,heartsucker/securedrop,GabeIsman/securedrop,garrettr/securedrop,heartsucker/securedrop,jrosco/securedrop,harlo/securedrop,GabeIsman/securedrop,pwplus/securedrop,ageis/securedrop,GabeIsman/securedrop,kelcecil/securedrop,ageis/securedrop,chadmiller/securedrop,jeann2013/securedrop,kelcecil/securedrop,jaseg/securedrop,heartsucker/securedrop