Fix --no-ask-password

POSIX_ME_HARDER mode is disabled for localectl. It doesn't
make much sense in case of localectl, and there's little reason
for localectl to behave specially.
systemctl: mangle names when avoiding dbus

Unit names were mangled in function enable_unit only when dbus was
used. This patch adds mangling also when the dbus is not in use.

This makes it possible to say e.g.:
   systemctl --root=/path enable cups
without spelling cups.service out in full.