bug#34567: Bogus 'upower-service' deprecation message

[Mark H Weaver]

My OS config includes a reference to 'upower-service', which is now
deprecated, but the deprecation message is bogus:

  address@hidden ~$ guix system build /etc/config.scm --verbosity=1
  /etc/config.scm:149:19: warning: 'slim-service' is deprecated, use 
'slim-service-type' instead
  /etc/config.scm:156:19: warning: 'upower-service' is deprecated, use 'Return 
a service that runs @uref{http://upower.freedesktop.org/,
  @command{upowerd}}, a system-wide monitor for power consumption and battery
  levels, with the given configuration settings.  It implements the
  @code{org.freedesktop.UPower} D-Bus interface, and is notably used by GNOME.' 
instead
  building 
/gnu/store/nwdjz1mkvcc4ic65mgw5i94ig3qzp8kf-libjpeg-turbo-2.0.2.tar.gz.drv...
  [...]

       Mark