webapp: do 302 redirects for suites / aliases
webapp: do 302 redirects for suites / aliases

Versions may change in the future, browsers shouldn't keep those
redirects cached.

Signed-off-by: Stefano Zacchiroli <d7cdf09fc0f0426e98c9978ee42da5d61fa54986@upsilon.cc>

zacchiro/debsources,zacchiro/debsources,matthieucan/debsources,clemux/debsources,zacchiro/debsources,matthieucan/debsources,matthieucan/debsources,oorestisime/debsources,devoxel/debsources,clemux/debsources,vivekanand1101/debsources,clemux/debsources,oorestisime/debsources,devoxel/debsources,oorestisime/debsources,Debian/debsources,oorestisime/debsources,devoxel/debsources,oorestisime/debsources,clemux/debsources,matthieucan/debsources,Debian/debsources,devoxel/debsources,devoxel/debsources,vivekanand1101/debsources,zacchiro/debsources,Debian/debsources,vivekanand1101/debsources,vivekanand1101/debsources,Debian/debsources,zacchiro/debsources,vivekanand1101/debsources,matthieucan/debsources,Debian/debsources,clemux/debsources