update-ng: be more resilient to failures when forcing triggers
update-ng: be more resilient to failures when forcing triggers

... to, e.g., avoing throwing away all checksums computation when the last
package throws an exception!

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