I don't like this.  It shouldn't be required to download both architectures in order to install just one.  This is another reason why your pull request currently breaks `install-spotify.sh`; even though it happily downloaded the `amd64`, the `rpmbuild` fails due to the `i386 .deb` missing:

    error: Bad file: /home/adam/rpmbuild/SOURCES/spotify-client_0.9.0.133.gd18ed58.259-1_i386.deb: No such file or directory