I can confirm this problem. After manually fsck the root partition and still get the same initramfs shell I downgraded e2fsprogs and libext2fs2 to the previous versions I found in /var/cache/apt/archives (1.45.2-1) and the system booted again.
- Bug#932854: Missing dependency for initramfs-to... Colin Booth
- Bug#932854: Missing dependency for initram... Miguel A. Vallejo
- Processed: Re: Bug#932854: Missing depende... Debian Bug Tracking System
- Bug#932854: Missing dependency for initram... Sven Joachim
- Processed: Re: initramfs-tools-core: Pleas... Debian Bug Tracking System
- Bug#932854: initramfs-tools-core: Please d... rharwood
- Bug#932854: initramfs-tools-core: Plea... Sven Joachim
- Processed: Re: Bug#932854: initramfs-tools... Debian Bug Tracking System
- Bug#932854: marked as done (initramfs-tool... Debian Bug Tracking System

