hook_checksums.py: fix typo in loop variable
hook_checksums.py: fix typo in loop variable

sophiejjj/debsources,clemux/debsources,clemux/debsources,oorestisime/debsources,matthieucan/debsources,vivekanand1101/debsources,nonas/debian-qa,Debian/debsources,sophiejjj/debsources,devoxel/debsources,Debian/debsources,zacchiro/debsources,zacchiro/debsources,oorestisime/debsources,vivekanand1101/debsources,nonas/debian-qa,nonas/debian-qa,clemux/debsources,matthieucan/debsources,clemux/debsources,sophiejjj/debsources,zacchiro/debsources,zacchiro/debsources,nonas/debian-qa,sophiejjj/debsources,clemux/debsources,matthieucan/debsources,matthieucan/debsources,vivekanand1101/debsources,zacchiro/debsources,vivekanand1101/debsources,oorestisime/debsources,devoxel/debsources,matthieucan/debsources,Debian/debsources,oorestisime/debsources,Debian/debsources,vivekanand1101/debsources,devoxel/debsources,Debian/debsources,devoxel/debsources,sophiejjj/debsources,oorestisime/debsources,devoxel/debsources