systemctl: allow multiple arguments to --type

This mirrors --property, and is generally useful.

New functionality is used in bash completion.

In case of zsh completion, new functionality is less useful
because of caching. Nevertheless, zsh completion for restart
is made to behave more-or-less the same as bash completion.
At least sockets can be restarted.
systemctl: show the name of failing unit in red

It makes it easier to pick out problematic unit
names from a long list.
errno is positive

Make sure we compare errno against positive error codes.
The ones in hwclock.c and install.c can have an impact, the
rest are unlikely to be hit or in code that isn't widely
used.

Also check that errno > 0, to help gcc know that we are
returning a negative error code.
hwclock: use _cleanup_ to simplify function
bus: make kdbus work so that we can exchange real messages

We have ignition, we have tremendous fire!