I just hit this bug as well. I have a bash script that sets the WM I choose (from when I was trying different ones - now I always choose "awesome"), and then does "exec xinit". Ultimately xinitrc is running the command "awesome" which starts Awesome WM. No idea what Awesome does internally, but it has always worked.
The /dev/tty* files all exist, but while /dev/tty has perms of rw-rw-rw-, /dev/tty1 has rw------- and the others including tty0 have rw--w---- I have no idea if that is normal. I find if I chmod them to 666, I no longer get the unable to open tty0 message, but get a blank screen that accepts no input. I have to use the reset button for soft restart, and then examining the logs show a message when it tries to modeset "Permission denied [13]" Both udev and xorg were upgraded at the same time, I first downgraded 1.17.2-3 to 1.17.2-2 (and 7.7+12 to 7.7+11), the problem persisted. So I downgraded udev from 227 to 226 (and I know for udev that 226 is what I was on before), but the problem persisted. I don't know what version of xorg I had before (although I shouldn't be that far behind), so I will try going back further next. Although snapshot.debian.org says that 1.17.2-2 was seen on 2015-08-21, So that really should have been the one I was on, no way I was that out of date... Any advice is appreciated, if there are any tests I can do, let me know... Kelly Clowers