Stop closing the log-port port

This part of the soft-port seems to be called, but I don't know why, and
trying to close the output port causes issues.

guix-data-service/jobs/load-new-guix-revision.scm

@@ -64,7 +64,8 @@
              (force-output output-port))
            #f ; fetch one character
            (lambda ()
-             (close-port output-port))
+             ;; close port
+             #f)
            #f) ; number of characters that can be read
    "w"))