cleanup /etc/apt/apt.conf.d/00notiy-hook on existing systems
00notiy-hook was renamed to 00notify-hook in
'debian: Renamed incorrect filename: 00notiy-hook -> 00notify-hook'
https://github.com/QubesOS/qubes-core-agent-linux/commit/15f1df49474368510180c8b232a69c2a5dce9533
but the old file was not removed.
(Files in /etc do not automatically get removed on Debian systems when these are removed from the package.)
This is an independent, but supporting fix for:
'Improved upgrade notifications sent to QVMM.'
- https://github.com/marmarek/qubes-core-agent-linux/pull/39
- https://github.com/QubesOS/qubes-issues/issues/1066#issuecomment-150044906
Added debian/qubes-core-agent.maintscript.
Patrick Schleizer