Bug#401183: linux-image-2.6.17-2-xen-686.postinst not idempotent

[Robert Bihlmeyer <robbe@orcus.priv.at>]

Package: linux-image-2.6.17-2-xen-686
Version: 2.6.17-9
Severity: serious

ObSeverity: policy 6.2 looks like a MUST to me, though not explicitly

When configuring this package a second time the
            update-initramfs -c -k 2.6.17-2-xen-686
bombs because the initramfs file is already present. Maybe the old file should
be deleted before this? Another option is to not check the existence of "$2",
but whether the initramfs file exists to decide between "-c" and "-u".