acpi-fpdt: break on zero or negative length read

https://bugzilla.redhat.com/show_bug.cgi?id=1027478
man: wording and grammar updates

This is a recurring submission and includes corrections to various
issue spotted: comma setting, missing words/preposition choice.
man: add rationale into systemd-halt(8)

The explanation is from
http://people.debian.org/~stapelberg/docs/systemd-dependencies.html
Support additional argument in reboot

reboot syscall can be performed with an additional argument. In some
systems this functionality can be useful to modify the mode of the
next boot performed by the bootloader.
test: remove duplicated code
systemd-python: convert keyword value to string

Allows using journal.send('msg', PRIORITY=journal.LOG_CRIT)

Before this commit this results in
TypeError: cannot concatenate 'str' and 'int' objects
and requires passing PRIORITY value as string to work.
systemctl: make LOAD column width dynamic

Otherwise 'not-found' overflows into the ACTIVE column.
udevadm-settle: add parameters checking
udevadm-trigger: add parameters checking
zsh-completion: add missing options for systemd-run
Make hibernation test work for swap files

Suspend to disk works for swap files too (even if it is located
on an ecrypted file system):
https://www.kernel.org/doc/Documentation/power/swsusp-and-swap-files.txt
test-strv: add strv_split, strv_split_newline, strv_remove_prefix
core: require $XDG_RUNTIME_DIR to be set for user instances

It seems that some places use /run otherwise, which isn't going to work.
udevadm-settle: add missing brace