Remove systemd-hack-up-the-source.hook script

No longer necessary after the switch from gitpkg to git-buildpackage.
Remove udev.vim syntax file

vim provides syntax highlighting support for udev rules since around
2006.
Remove duplicate PATH
Mask remaining services provided by the initscripts package

and document in more detail why certain services have been masked.

Closes: #659264
Cherry-pick upstream fix for journal file permissions.
Clean up libsystemd-login-dev autopkgtest

Rename "api" autopkgtest to "build-login", and stop requiring that
sd_login_monitor_new() succeeds. It doesn't in many environments like schroot
or after upgrades from < 204, and the main point of the test is to check that
libsystemd-login-dev has correct contents and dependencies. Drop
"isolation-machine" requirement.
Map some rcS.d init script dependencies to their systemd equivalent.
Update Depends on initscripts to the version with a systemd-compatible mountnfs ifup hook.
Add Breaks on lvm2 versions without native systemd support.
Add /run/shm -> /dev/shm symlink in debian/tmpfiles.d/debian.conf.
Do not fail udev upgrades if the udev service is already runtime-masked when the preinst script is run.
Add Pre-Depends on systemd to systemd-sysv.

This avoid risking that the sysv-compatible symlinks become dangling on a partial install.
Note that the Pre-Depends is unversioned to facilitate upgrades to newer systemd versions,
and that the versioned Depends is kept to ensure that user doesn't get confused to thinking
they are running a different systemd version then they are.
Ensure that systemctl is usable right after being unpacked.
Add support for rcS.d init scripts to the sysv-generator.
Do not order rcS.d services after local-fs.target if they do not explicitly depend on $local_fs.
Map rcS.d init script dependencies to their systemd equivalent.
Special-case some dependencies for sysv init scripts for better backwards compatibility.

Also drop Order-remote-fs.target-after-local-fs.target.patch. As DefaultDependencies=yes
implies After=local-fs.target this is only needed for rcS.d services depending on $remote_fs
but not $local-fs, and with this commit those get a dependency on local-fs.target instead
of remote-fs.target anyway.
Fix various features that didn't work if /usr wasn't mounted in the initramfs.

Amongst other things, this commit drops the special-casing of /etc/localtime
when /usr is not part of the root fs, as timedated does not care about the
file content, only the symlink value.

To fix the real problem, that timezoned needs zoneinfo data which is located
in /usr, add RequiresMountsFor=usr/share/zoneinfo to the service file.
Rename one incredibly poorly named patch.
Merge branch 'master' into experimental

Conflicts:
	debian/changelog
	debian/control
	debian/patches/Map-rcS.d-init-script-dependencies-to-their-systemd-.patch
	debian/patches/series
	debian/systemd.links
	debian/tmpfiles.d/debian.conf