Fixes <https://issues.guix.gnu.org/55450>.
Fixes a bug introduced in 211fe3f66e
whereby the inetd-spawned process would run as root (it would still run
in a separate user namespace, with UID 1000 inside of it, but had the
authority of root).
* gnu/services/messaging.scm (bitlbee-shepherd-service): Pass #:user
and #:group to 'make-inetd-constructor'. Remove "-u bitlbee" argument
to BITLBEE*.
